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Ch. 12 Review Questions- ANSWERS
***This will be for a homework grade. Have it completed by class tomorrow.***
1) What is the reaction force?
ball bumps head
2) An object with a mass of 2.0 kg accelerates 2.0m/s2 when an unknown force is applied to it.
What is the amount of force? Include units.
4N
3) An object with a mass of 2,300kg has a force of 6.2N applied to it. What is the resulting
acceleration of the object? Include units and give me 4 places behind the decimal.
0.00269 m/s2
4) A bag of sugar has a mass of 2.26kg. What is its weight in Newtons on Earth? Include units and
round 2 places behind the decimal.
22.15N
5) The momentum of an empty plane is 3,790 kg*m/s when its velocity is 230m/s. Find the mass of
the plane. Include units and round 2 places behind the decimal.
16.48 kg
6) If a golf ball with a mass of 0.056kg has a momentum of 4.67 kg*m/s, what is its velocity?
Include units and give 2 places behind the decimal.
83.39m/s
7) Find the momentum of a 2,543kg car that is moving at 34.6m/s. Include units and round to the
nearest whole number.
87,988 kg*m/s
8) Which of the following relationships is correct?
a) 1N = 1 kg
b) 1N = 1 kg*m/s
c) 1N = 1 kg*m
d) 1N = 1 kg*m/s^2
.
9) When a pair of balanced forces acts on an object (same force, but opposite in direction), the net
force that results is
Equal to zero
.
10) As you push a cereal box across a tabletop, the sliding friction acting on the cereal box
Acts in the direction opposite of motion
.
11) Projectile motion is caused by
The downward force of gravity and an initial forward velocity
.
12) An orange might roll off your cafeteria tray when you stop suddenly because of
The orange’s inertia
.
13) When an unbalanced force acts on an object (mass),
a) the object's motion does not change
b) the object accelerates
c) the weight of the object decreases
d) the inertia of the object increases
.
14) What kind of friction occurs as a fish swims through water?
Fluid friction
.
15) The forces acting on a falling object are
Gravity and air resistance
.
16) According to Newton's 2nd Law of motion, the acceleration of an object equals the net force
acting on the object divided by the object's
mass
.
17) Your weight equals your
a) mass
b) mass divided by the net force acting on you
c) mass times the acceleration due to gravity
d) mass times your speed
.
18) What is conserved when a speeding car collides with a car sitting still (causeing that car to
accelerate)?
momentum
.
19) Which of the following universal forces is the most effective over long distances?
Gravitational force
.
20) The force that keeps an object moving in a circle is called (think moon orbiting around Earth)
Centripetal force
.
21) An archer shoots an arrow. The action force is the bowstring against the arrow. The reaction
force is...
Arrow push against the bowstring
.
22) What is the total net force?
a) 5 N, right
b) 0 N, right
c) 8 N, left
d) 5 N, left
.
23) Which object would have the most momentum if they were all traveling at the same velocity?
a) bowling ball
b) bicycle
c) elephant
d) mouse
.
24) In which of the following are action and reaction forces involved?
a) when a tennis racket strikes a tennis ball
b) when stepping from a curb
c) when rowing a boat
d) all of these have action-reaction forces
.
25) The centripetal force acting on a satellite in orbit
a) acts as an unbalanced force on the satellite
b) changes the direction of the satellite
c) is a center-directed force
d) all of these
.