5.4 × 10³ J of heat is used to convert 400 grams of ice at 0°C to
water at 0°C. What is the entropy change of the system? Correct
Answers 19.8j/k
A 5 cm tall object is placed 25 cm away from a concave mirror
that has a radius of curvature of 10 cm. What is the size of the
image that is produced? Correct Answers 1.25 cm
A 5 kg block attached to a spring oscillates with simple
harmonic motion on a horizontal frictionless surface. Which of
the following is true about the energy of the system? Correct
Answers The kinetic energy of the spring is at a maximum
when the block is at equilibrium, position
A ball is rolled off a horizontal table with a velocity, v. If the
table has a height which of the following represents the distance
that the ball will land from the table when it hits the ground?
Correct Answers V x Sqrt 2h/g
A block of metal weighs 60 N in air and 40 N underwater. What
is the density of the block? Correct Answers 3000kg/m3
A bullet with a mass of 25 grams is traveling at a speed of 250
m/s. The bullet encounters a 35-kg wooden block at rest and
upon impact, gets embedded within the block. What is the
velocity with which the objects move together after the
collision? Correct Answers V(a+b)f=mavai/(ma+mb)
, A distance r separates two charges. The charges attract each
other with force Fₑ. If the distance between the two charges is
halved and each charge's magnitude is doubled, what is the
magnitude of the new force between the two? Correct Answers
16 Fe
A girl throws a basketball straight up in the air. Which of the
following statements is true about the ball while it is in the air?
Correct Answers The velocity and acceleration of the ball are in
the same direction while the ball is on its way down
A large box that weighs 20,000 N sits atop a hydraulic lift, as
shown below. If the small piston's radius is 5 cm and the radius
of the large piston is 20 cm, what force is F required to lift the
box? Correct Answers 1250 N
A machine's output is 4000 Joules, and its frictional losses are
2000 Joules. What is the efficiency of the machine? Correct
Answers 67%
A man walks 56 km exactly southeast in a field before turning
around and walking 76 km to the north. Which of the following
vectors represents the man's total displacement? Correct
Answers 43 km at 22.5 degrees north of east- this is the only
problem that walks northeast, so draw the problem out
A ray of light in air strikes a material of unknown index of
refraction at an angle of incidence of 30 degrees. The refracted
angle is measured to be 18.21°; what is the refractive index of
the material? Correct Answers 1.00xsin(30)/sin(18.21)