Download CPphysics review 2-10

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Honors Physics Final Exam Review 2
Chapters 5- work and energy,6- momentum,
7 – rotations and gravity
1) A box is pushed around a square room and back to its
original starting position. The total work done by
friction is
a) positive b) negative
c) zero d) depends on mass
2) When a car's speed doubles, what happens to its
kinetic energy?
a) It is halved
b) It is unchanged
c) It is doubled
d) It is quadrupled
3) A person pushes a 10 kg box at a constant velocity
over a distance of 4 m. The coefficient of kinetic
friction between the box and the floor is 0.3. How much
work does the person do in pushing the box? (the
applied force is horizontal).
a) 12.0 J
b) 29.4 J
c) 118 J
d) 392 J
4) A worker does 500 J of work on a 10 kg box. If the
box transfers 375 J of heat to the floor through the
friction between the box and the floor, what is the
velocity of the box after the work has been done on it?
a) 5 m/s
b) 10 m/s
c) 12.5 m/s
d) 25 m/s
5) A person on the street wants to throw an 8 kg block
up to a person leaning out of a window 5 m above street
level. With what velocity must the person throw the
block so that it reaches the person in the window?
a) 3.50 m/s
b) 9.90 m/s
c) 28.0 m/s
d) 98.1 m/s
6) An object is moving at 3.3 m/s and has 220J of
energy. What the mass of the object?
a) 40.4 kg
b) 12.2 kg
c) 66.7 kg
d) 133 kg
7) A 25kg child standing at the top of a slide has 687J
of potential energy due to gravity. What is the height
of the slide?
a) 2.2 m
b) 2.8 m
c) 27 m
d) 70 m
8) What is the average power supplied by a 60kg person
running up a hill rising a vertical distance of 4m in 4.2s?
a) 380 W
b) 560 W
c) 610 W
d) 670 W
9) A 3kg block falls from a height of 10m. What will its
KE be just before it hits the ground?
a) 98.0 J
b) 196 J
c) 14.0 J
d) 294 J
10) A mass of 1.5kg is hung from a spring, stretching it
10cm. What is the spring constant?
a) 14.7 N/m
b) 147 N/m
c) 29.4 N/m
d) 294 N/m
11) A 50g marble is rolled up a frictionless ramp with an
initial velocity of 10m/s. What is the maximum vertical
height it can reach?
a) 2.55 m
b) 0.509 m
c) 5.10 m
d) 25.5 m
13) The change in an object's momentum is equal to
a) the product of the mass of the object and the
time interval.
b) the product of the force applied to the object and
the time interval.
c) the time interval divided by the net external force.
d) the net external force divided by the time interval.
14) Two ice skaters face each other. One skater's mass
is 48 kg, and the other's mass is 55 kg. If the skaters
push away from each other,
a) their total momentum decreases.
b) their total momentum increases.
c) their total momentum doubles.
d) their momenta are equal but opposite.
15) In an inelastic collision
a) momentum is conserved
b) kinetic energy is conserved
c) neither momentum nor kinetic energy is conserved
d) both momentum and kinetic energy are conserved
16) You need to stop a rolling cart. Increasing the time
interval over which the force is applied requires
a) less force
b) more force
c) same force d) depends on angle
12) A 9kg block of ice initially moving at 15m/s slides
and comes to rest on a surface where the coefficient of
friction is 0.04. How far does the block slide before
coming to a stop?
a) 28.1 m
b) 35.3 m
c) 287 m
d) 103 m
17) An astronaut at rest in outer space throws an
object away from himself. The total momentum of the
system is
a) positive b) negative
c) zero d) depends on the direction
18) What velocity must a 1340 kg car have in order to
have the same momentum as a 2680 kg truck traveling
at a velocity of 15 m/s to the west?
a) 60 m/s W
b) 60 m/s E
c) 30 m/s W
d) 30 m/s E
*19) A 0.2kg baseball if pitched with a velocity of 40
m/s and is then batted back to the pitcher with a
velocity of 60 m/s. What is the magnitude of change in
the ball's momentum?
a) 4 kg·m/s
b) 8 kg·m/s
c) 2 kg·m/s
d) 20 kg·m/s
20) A diver with a mass of 80.0 kg jumps from a dock
into a 130.0 kg boat at rest on the west side of the
dock. If the velocity of the diver in the air is 4.10 m/s
to the west, what is the final velocity of the diver after
landing in the boat (diver and boat move with same
speed)
a) 2.52 m/s W
b) 2.52 m/s E
c) 1.56 m/s W
d) 1.56 m/s E
21) A 400g snowball has a momentum 5.2 kg·m/s. What
is its velocity?
a) 0.013m/s
b) 2.1 m/s
c) 7.7 m/s
d) 13.0 m/s
22) A 5g plastic bullet is loaded into a 115g toy gun. The
bullet is fired causing the gun to recoil at a speed of 1.3
m/s. What is the speed of the bullet?
a) 10.8 m/s
b) 29.9 m/s
c) 60.1 m/s
d) 92.3 m/s
24. ____ A wheel is spinning with an angular velocity of 22rad/s. How many rotations has it completed after
7 seconds?
a) 3.14 rotations
b) 49 rotations
c) 154 rotations
d) 24.5 rotations
25. ____ The Earth and moon are separated by a distance of 3.84x105 m. The mass of the Earth is 6x1024 kg
and it exerts a gravitational force of 2x1026 N with the moon. What is the mass of the moon?
a) 4.9x1012 kg
b) 1.9x1017 kg
c) 6.8x1021 kg
d) 7.4x1022 kg
26. ____ The force of gravity between the earth and a satellite in orbit is 1200N. If the distance between
the satellite and the center of the earth is reduced to half its original value, how will the force of
gravity on the satellite change?
a) it will be reduced by half
b) it will double
c) it will be 4 times as much
d) it will remain the same.
27. ____ A 0.35 kg ball is attached to a string and rotates in a horizontal circular plane. If a tangential
speed of 15.2 m/s produces a centripetal force of 12.8 N, what is the radius of the string?
a) 6.3 m
b) 2.5 m
c) 18 m
d) 0.42 m
28. ____ If the torque required to loosen a bolt on a wheel is 40 N·m and the maximum force exerted by a
mechanic is 133 N, at least how far from the bolt must the mechanic apply the force?
a) 3.33 cm
b) 30.0 cm
c) 53.2 cm
d) 1.21 cm