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Newton’s Law Test 2010 v.A
Period ______
Honors Physics
Date: _____________
E. Burns
Part 1: Multiple Choice (2 points each)
ANSWERS: 1 _____ 2_____ 3_____ 4_____ 5_____
1. A net force F accelerates a mass m with an acceleration of a. If the same net force is applied to mass 2m, then the
acceleration will be
a. 4a
b. 2a
c. a/2
d. a/4
2. A 20-ton truck collides with a 1500 lb car and causes a lot of damage to the car. Since a lot of damage is done on
the car,
a. the force on the truck is greater then the force on the car.
b. the force on the truck is equal to the force on the car.
c. the force on the truck is smaller than the force on the car.
d. the truck did not slow down during the collision.
3. An object of mass m is hanging by a string from the ceiling of an elevator. The elevator is moving upward but
slowing down. What is the tension in the string?
a. less than mg
b. exactly mg
c. greater than mg
d. zero
4. A stone is thrown straight up. At the top of its path, the net force acting on it is
a. greater than its weight
b. greater than zero, but less than its weight
c. instantaneously equal to zero
d. equal to its weight
5. A packing crate slides down an inclined ramp at constant velocity. Thus we can deduce that
a. a frictional force is acting on it
b. a net force downward force is acting on it
c. it may be accelerating
d. the gravitational force acting on the object is very small
Part 2: Free Response
Complete 3 of the following four problems. 25 points each.
1] A sign is suspended by two wires, as the drawing shows. Find the tension in the two wires.
43.0
55.0
43.0 kg
SIGN
2] A person whose weight is 520 N is being pulled up vertically by a rope from the bottom of a cave that is 35.1 m deep.
The maximum tension that the rope can withstand without breaking is 569 N. What is the shortest time, starting from rest,
in which the person can be brought out of the cave?
3] Two blocks, mA and mB are connected by a mass-less rope. mA = 5.0 kg and mB = 7.0 kg. The coefficient of kinetic
friction between the blocks and the surface upon which they move is 0.20. Handles are attached to each block.
a. What is the maximum tension in the rope if someone pulls on one of the handles causing the system to move
at 3.0 m/s2? (Hint: you must determine in which direction you must pull to achieve the maximum tension)
b. What is the tension in the rope if the someone pulls to the right on mB causing the system to move at a
constant speed of 6.0 m/s?
A
B
4] In the diagram below, the 8 kg mass moves up the incline where the coefficient of kinetic friction is 0.4. Assume the
pulley is frictionless and the string is mass-less.
A] Determine the friction force acting on the 8 kg mass
B] Determine the acceleration of each mass
8 kg
20 kg
37