General Physics - Exam 1 || All Answers Are Correct 100%.
A rotary lawn mover spins its sharp blade rapidly over the lawn and cuts the top off the grasses. Would the blade still cut the grasses if they weren't attached to the ground? correct answers Yes
Why does a stationary skater remain stationary? correct answers A body at rest tends to remain at
rest
This observed behavior is known as inertia
Why does a moving skater continue moving? correct answers A body in motion tends to remain in motion
This behavior is the second half of inertia
Why does a skater need ice or wheels to skate? correct answers Real-world complications usually mask inertia
Solution: minimize or overwhelm complications
How does a skater start or stop moving? correct answers A net force causes the skater to accelerate
Several soda cans are lying on their sides on a table. To find the full can of soda, without lifting anything, you should correct answers Push each can and observe its acceleration
As you jump across a small stream, does a horizontal force keep you moving forward? If so, what is the force? correct answers No, there is no horizontal force. You continue to move forward because of inertia
Stamping your feet cleans the snow off of them because correct answers the snow on your feet has inertia
The back of your car seat has a head rest to protect your neck during a collision. The type of collision which causes your head to press against the headrest is correct answers a rear-end collision
Loose objects on the dashboard slide to the right when the car turns suddenly to the left because correct answers they have inertia
If your car has a mass of 745 kg, how much force is required to accelerate it forward at 4.74 m/s^2 correct answers F = 3531 N
F=ma An elevator is moving downward and coming to a stop. What is its acceleration, if any? correct answers Its acceleration is upwards
Suppose you have two cars, and the larger car is twice as massive as the smaller one. If you and a
friend push on them so that their acceleration are equal, how must the forces applied to the cars compare? correct answers The force on the larger car is twice that on the smaller car
Suppose you have a car traveling down the road at constant speed and not changing direction. It is experiencing gravity, wind resistance and frictional forces from the road. What can be said about the car's acceleration? correct answers It is not accelerating because it has constant velocity
Tapping your toothbrush on the sink dries it off because correct answers the water on the toothbrush has inertia
An unseatbelted driver can be injured by the steering wheel during a head-on collision. The driver hits the steering wheel when the car suddenly comes to a stop because correct answers the driver's head has inertia
One type of home coffee grinder has a small blade that rotates very rapidly and cuts the coffee beans into powder. Nothing prevents the coffee beans from moving. The reason the beans don't get out of the way when the blade begins to push on them is correct answers they have inertia
A blacksmith usually hammers hot metal on the surface of a massive steel anvil. The reason this is more efficient than hammering the hot metal on the surface of a thin steel plate is correct answers the massive anvil has more inertia
Which of the following devices on a car can be used to cause the car to accelerate? correct answers The gas pedal, the brake pedal, the steering wheel
Suppose you are at a stop light and realize that an important antique physics textbook sale ends in five minutes. Naturally, you start off very rapidly. To you, some papers on the dashboard fly straight backwards. To an observer on the ground they correct answers remained where they were
Suppose you are driving north and you suddenly hit your brakes to avoid a dog in the road. As you come to a stop your acceleration is directed correct answers South
Under what conditions are the values of average speed and the magnitude of the average velocity
equal? correct answers When moving in a straight line and not turning around
To cause a 25 kg object to experience an acceleration of 2 m/s2 the net force that needs to be applied to the object is correct answers 50 N
F=ma An object experiences a net force of 20 N and has an acceleration of 4 m/s2. The object's mass must be correct answers 5 kg
F=ma
Suppose that the night before your big physics exam you stayed up late watching stand - up physics comedians. Sides sore from having laughed too hard you come to class and are in the middle of the test when you get stuck. You are doing a calculation problem and know the answer
must have units of velocity and are searching for a possible formula. Which of the following formulae would work for the problem? correct answers acceleration x time
Suppose I throw a ball upward into the air. After the ball leaves my hand, is there any force pushing the ball upward? Neglect any effects due to air. correct answers No
Why does a dropped ball fall downward? correct answers Earth's gravity exerts a force on the ball
That force is the ball's weight
Do different balls fall at different rates? correct answers No, they all fall together
If we could eliminate air resistance, would a light sheet of paper and a heavy book fall at the same rate? correct answers No
Can a ball move upward and still be falling? correct answers Yes
You jump upward from a springboard and dive gracefully into the pool. At the peak of your jump, your velocity is correct answers changing, but your acceleration is constant
Does a ball's horizontal motion affect its fall? correct answers No. ball falls vertically but coasts horizontally
A ball falls from rest for 5 seconds. Neglecting air resistance, how does the speed increase in the first second compare to the speed increase in the last second? correct answers The speed change is the same during each of the 5 seconds
Neglect air resistance in this question. If you drop a ball from a height of 4.9 m, it will hit the ground 1 s later. If you fire a bullet exactly horizontally from a height of 4.9 m, it will also hit the
ground 1 s later. Explain. correct answers The motion in the vertical and horizontal direction are independent of each other.
An acorn falls from a branch located 9.8 m above the ground. After 1 s of falling, the acorn's velocity will be 9.8 m/s downward. Why hasn't the acorn hit the ground? correct answers The acorn's average speed for the 1 s is less than 9.8 m/s
A rotary lawn mover spins its sharp blade rapidly over the lawn and cuts the top off the grasses. Would the blade still cut the grasses if they weren't attached to the ground? correct answers Yes
Why does a stationary skater remain stationary? correct answers A body at rest tends to remain at
rest
This observed behavior is known as inertia
Why does a moving skater continue moving? correct answers A body in motion tends to remain in motion
This behavior is the second half of inertia
Why does a skater need ice or wheels to skate? correct answers Real-world complications usually mask inertia
Solution: minimize or overwhelm complications
How does a skater start or stop moving? correct answers A net force causes the skater to accelerate
Several soda cans are lying on their sides on a table. To find the full can of soda, without lifting anything, you should correct answers Push each can and observe its acceleration
As you jump across a small stream, does a horizontal force keep you moving forward? If so, what is the force? correct answers No, there is no horizontal force. You continue to move forward because of inertia
Stamping your feet cleans the snow off of them because correct answers the snow on your feet has inertia
The back of your car seat has a head rest to protect your neck during a collision. The type of collision which causes your head to press against the headrest is correct answers a rear-end collision
Loose objects on the dashboard slide to the right when the car turns suddenly to the left because correct answers they have inertia
If your car has a mass of 745 kg, how much force is required to accelerate it forward at 4.74 m/s^2 correct answers F = 3531 N
F=ma An elevator is moving downward and coming to a stop. What is its acceleration, if any? correct answers Its acceleration is upwards
Suppose you have two cars, and the larger car is twice as massive as the smaller one. If you and a
friend push on them so that their acceleration are equal, how must the forces applied to the cars compare? correct answers The force on the larger car is twice that on the smaller car
Suppose you have a car traveling down the road at constant speed and not changing direction. It is experiencing gravity, wind resistance and frictional forces from the road. What can be said about the car's acceleration? correct answers It is not accelerating because it has constant velocity
Tapping your toothbrush on the sink dries it off because correct answers the water on the toothbrush has inertia
An unseatbelted driver can be injured by the steering wheel during a head-on collision. The driver hits the steering wheel when the car suddenly comes to a stop because correct answers the driver's head has inertia
One type of home coffee grinder has a small blade that rotates very rapidly and cuts the coffee beans into powder. Nothing prevents the coffee beans from moving. The reason the beans don't get out of the way when the blade begins to push on them is correct answers they have inertia
A blacksmith usually hammers hot metal on the surface of a massive steel anvil. The reason this is more efficient than hammering the hot metal on the surface of a thin steel plate is correct answers the massive anvil has more inertia
Which of the following devices on a car can be used to cause the car to accelerate? correct answers The gas pedal, the brake pedal, the steering wheel
Suppose you are at a stop light and realize that an important antique physics textbook sale ends in five minutes. Naturally, you start off very rapidly. To you, some papers on the dashboard fly straight backwards. To an observer on the ground they correct answers remained where they were
Suppose you are driving north and you suddenly hit your brakes to avoid a dog in the road. As you come to a stop your acceleration is directed correct answers South
Under what conditions are the values of average speed and the magnitude of the average velocity
equal? correct answers When moving in a straight line and not turning around
To cause a 25 kg object to experience an acceleration of 2 m/s2 the net force that needs to be applied to the object is correct answers 50 N
F=ma An object experiences a net force of 20 N and has an acceleration of 4 m/s2. The object's mass must be correct answers 5 kg
F=ma
Suppose that the night before your big physics exam you stayed up late watching stand - up physics comedians. Sides sore from having laughed too hard you come to class and are in the middle of the test when you get stuck. You are doing a calculation problem and know the answer
must have units of velocity and are searching for a possible formula. Which of the following formulae would work for the problem? correct answers acceleration x time
Suppose I throw a ball upward into the air. After the ball leaves my hand, is there any force pushing the ball upward? Neglect any effects due to air. correct answers No
Why does a dropped ball fall downward? correct answers Earth's gravity exerts a force on the ball
That force is the ball's weight
Do different balls fall at different rates? correct answers No, they all fall together
If we could eliminate air resistance, would a light sheet of paper and a heavy book fall at the same rate? correct answers No
Can a ball move upward and still be falling? correct answers Yes
You jump upward from a springboard and dive gracefully into the pool. At the peak of your jump, your velocity is correct answers changing, but your acceleration is constant
Does a ball's horizontal motion affect its fall? correct answers No. ball falls vertically but coasts horizontally
A ball falls from rest for 5 seconds. Neglecting air resistance, how does the speed increase in the first second compare to the speed increase in the last second? correct answers The speed change is the same during each of the 5 seconds
Neglect air resistance in this question. If you drop a ball from a height of 4.9 m, it will hit the ground 1 s later. If you fire a bullet exactly horizontally from a height of 4.9 m, it will also hit the
ground 1 s later. Explain. correct answers The motion in the vertical and horizontal direction are independent of each other.
An acorn falls from a branch located 9.8 m above the ground. After 1 s of falling, the acorn's velocity will be 9.8 m/s downward. Why hasn't the acorn hit the ground? correct answers The acorn's average speed for the 1 s is less than 9.8 m/s
