Physics 121 Chapter 4 Questions with
complete solution 2025
An object is moving with constant velocity. Which of the following best
describes the force(s) acting on the object? - correct answer ✔The net force
acting on the object is zero.
An object is at rest on a tabletop. Earth pulls downward on this object with a
force equal in magnitude to mg. If this force serves as the action force, what is
the reaction force in the action-reaction pair? - correct answer ✔the object
pulling upward on Earth
A large truck collides head-on with a small car. The car is severely damaged
as a result of the collision. According to Newton's third law, how do the forces
acting between the truck and car compare during the collision? - correct
answer ✔The force on the truck is equal to the force on the car.
According to Newton's first law, when the net force acting on an object is zero,
the object must _____. - correct answer ✔have constant velocity
An elevator moves straight upward at a constant speed. Newton's first law
predicts that the net force acting on the elevator will _____. - correct answer
✔be zero
Imagine holding a basketball in both hands, throwing it straight up as high as
you can, and then catching it when it falls. At which points in time does a zero
net force act on the ball? Ignore air resistance. - correct answer ✔when you
hold the ball still in your hands before it is thrown
when you hold the ball still in your hands after catching it
complete solution 2025
An object is moving with constant velocity. Which of the following best
describes the force(s) acting on the object? - correct answer ✔The net force
acting on the object is zero.
An object is at rest on a tabletop. Earth pulls downward on this object with a
force equal in magnitude to mg. If this force serves as the action force, what is
the reaction force in the action-reaction pair? - correct answer ✔the object
pulling upward on Earth
A large truck collides head-on with a small car. The car is severely damaged
as a result of the collision. According to Newton's third law, how do the forces
acting between the truck and car compare during the collision? - correct
answer ✔The force on the truck is equal to the force on the car.
According to Newton's first law, when the net force acting on an object is zero,
the object must _____. - correct answer ✔have constant velocity
An elevator moves straight upward at a constant speed. Newton's first law
predicts that the net force acting on the elevator will _____. - correct answer
✔be zero
Imagine holding a basketball in both hands, throwing it straight up as high as
you can, and then catching it when it falls. At which points in time does a zero
net force act on the ball? Ignore air resistance. - correct answer ✔when you
hold the ball still in your hands before it is thrown
when you hold the ball still in your hands after catching it
