5 Steps to a 5 500 AP Physics Questions to Know by Test Day (2012)
Chapter 4. Newton’s Second Law
91. Two boys push a 5-kg box on a frictionless floor. James pushes the box with a 10.0-N force to the right. Louis pushes the box with an 8.0-N force to the left. What is the magnitude and direction of the box’s acceleration?
(A) 0 m/s2; the box does not move
(B) 0.4 m/s2 to the right
(C) 0.4 m/s2 to the left
(D) 1.6 m/s2 to the right
(E) 1.6 m/s2 to the left
92. A box of unknown mass (m) slides down a plane inclined at an angle (θ). The plane has a coefficient of friction (μ). Which of the following expressions would you use to calculate the rate of acceleration (a)?
(A) a = g(sinθ - μgcosθ)/m
(B) a = g(cosθ - μgsinθ)/m
(C) a = m(sinθ - μgcosθ)/g
(D) a = g(sinθ - μcosθ)
(E) a = g(cosθ - μsinθ)
93. You pull down on one side of a rope stretched across a pulley. Attached to the other side of the rope is a 10-kg box. How much force must you pull down on the rope to get the box to accelerate upward at a rate of 10 m/s2?
(A) 10 N
(B) 20 N
(C) 50 N
(D) 100 N
(E) 200 N
94. A jet takes off at an angle of 60° to the horizontal. The jet flies against a wind that exerts 1,000 N on it. The engines produce 20,000 N of thrust and the mass of the jet is 90,000 kg. What is the rate of the jet’s acceleration in the horizontal direction?
(A) 0.1 m/s2
(B) 0.2 m/s2
(C) 1.0 m/s2
(D) 5.0 m/s2
(E) 10 m/s2
95. This graph depicts the magnitudes and directions of two forces that act on an object. At which of the following times is the object accelerating?
(A) 0 s and 1 s
(B) 2 s and 5 s
(C) 4 s and 8 s
(D) 1 s and 7 s
(E) 5 s and 10 s
96. [For Physics C Students Only] The motion of a 10-kg object can be described by the following equation, x (t) = ⅓t3 - 2t2 + 3t + 2, where t is measured in s and x is measured in m. At what time will there be no net force acting on the object?
(A) 0 s
(B) 1 s
(C) 2 s
(D) 3 s
(E) 4 s
97. A boy pushes a 10-kg crate across the floor with a constant force of 10 N against a force of friction. The box accelerates at a rate of 0.1 m/s2. What is the magnitude of the opposing frictional force?
(A) 0 N
(B) 1 N
(C) 5 N
(D) 9 N
(E) 10 N
98. A 10-kg crate is on a plane that is inclined at an angle of 45°. The coefficient of friction is 0.1, and the downward direction is positive. What is the approximate rate of the box’s acceleration?
(A) 0 m/s2
(B) 4.2 m/s2
(C) 6.4 m/s2
(D) 8.7 m/s2
(E) 10 m/s2
99. Two masses are connected by a rope across a pulley. The mass on the left of the pulley is 5 kg, while the mass on the right is 10 kg. If the positive direction of the pulley is counterclockwise, what is the magnitude and direction of the acceleration?
(A) 0 m/s2
(B) −3.30 m/s2
(C) −5.0 m/s2
(D) 3.3 m/s2
(E) 5.0 m/s2
100. The acceleration of a 5-kg object over time is shown in this graph. What is the net force at 1 s?
(A) −10 N
(B) −5 N
(C) −2.5 N
(D) 5 N
(E) 10 N
101. A skier weighing 70 kg pushes off from the top of a ski slope with a force of 105 N. The slope is inclined at 30°. Assuming that the slope is frictionless, what is the initial rate of the skier’s acceleration?
(A) 0.5 m/s2
(B) 1 m/s2
(C) 2 m/s2
(D) 7 m/s2
(E) 11 m/s2
102. A soldier fires a musket with a 1-m-long barrel. The gases from the exploding gunpowder exert a constant net force of 50 N on a 0.010-kg bullet as it travels through the musket barrel. What is the bullet’s velocity as it leaves the musket barrel?
(A) 10 m/s
(B) 100 m/s
(C) 1,000 m/s
(D) 10,000 m/s
(E) 100,000 m/s
103. [For Physics C Students Only] An object’s position with time is depicted in this graph. At which time will there be no net force acting on the object?
(A) 0 s
(B) 1 s
(C) 2 s
(D) 3 s
(E) 4 s
104. A block with a mass of 30 kg is located on a frictionless tabletop. This block is connected by a rope to another block with a mass of 10 kg. The rope is looped through a pulley on the table’s edge so that the less massive block is hanging over the edge. Consider counterclockwise rotation of the pulley as positive. What is the rate of acceleration of the larger block across the table?
(A) −0.5 m/s2
(B) −1 m/s2
(C) −2.5 m/s2
(D) 2.5 m/s2
(E) 1 m/s2
105. A jet flies at level flight. The engines produce a total of 20,000 N of thrust, the jet’s mass is 50,000 kg, and it accelerates at 0.3 m/s2. What is the magnitude of the air resistance against which the jet flies?
(A) 1,000 N
(B) 3,000 N
(C) 5,000 N
(D) 10,000 N
(E) 15,000 N
106. A boy is pushing a 50-kg crate across a frictionless surface. The velocity is changing with time as shown in this graph. What is the magnitude of the force that the boy applies to the crate?
(A) 5 N
(B) 10 N
(C) 15 N
(D) 20 N
(E) 25 N
107. A car with a mass of 1,000 kg travels at 30 m/s. The driver applies his brakes for a uniform deceleration and comes to a complete stop in 60 m. Assuming that the forward motion is positive, what is the magnitude and direction of the net force acting on the car?
(A) 7,500 N
(B) 5,000 N
(C) −1,000 N
(D) −5,000 N
(E) −7,500 N
108. A bowler applies a constant net force of 100 N on a 5-kg bowling ball over a time period of 1.5 s before he releases the ball. The ball starts from rest. What is its final velocity?
(A) 5 m/s
(B) 10 m/s
(C) 20 m/s
(D) 30 m/s
(E) 40 m/s
109. A place kicker kicks a football with an unknown velocity at an angle of 45° from the horizontal of level ground. The football travels against the wind. Which of the following statements is true?
(A) The time that it takes the football to hit the ground will be increased.
(B) The horizontal velocity will be less than it would have been had there been no wind.
(C) The time that it takes the football to hit the ground will be decreased.
(D) The football will travel further than it would have had there been no wind.
(E) The height of the football will be less than it would have been had there been no wind.
110. This graph depicts the velocity of a skydiver over time during a free fall. Which of the following statements is true?
(A) The net forces acting on the skydiver increase until the acceleration reaches its maximum and the velocity becomes constant.
(B) The net forces acting on the skydiver decrease until the acceleration reaches zero and the velocity becomes constant.
(C) There are no net forces acting on the skydiver.
(D) The net forces acting on the skydiver increase until the acceleration reaches zero and the velocity becomes constant.
(E) The net forces acting on the skydiver decrease until the acceleration reaches zero and the velocity becomes zero.
111. A girl pushes a 10-kg box from rest across a floor with a force of 50 N. The force of friction opposing her is 45 N. If the box uniformly accelerates to a final velocity of 2.0 m/s2, how long did it take to get to that velocity?
(A) 1 s
(B) 2 s
(C) 3 s
(D) 4 s
(E) 5 s
112. A rocket goes from rest to 9.6 km/s in 8 min. The rocket’s mass is 8.0 × 106 kg. Assuming a constant acceleration, what is the net force acting on the rocket?
(A) 1.6 × 105 N
(B) 9.6 × 105 N
(C) 9.6 × 106 N
(D) 1.0 × 107 N
(E) 1.6 × 108 N
113. A car travels at a constant velocity of 30 m/s. The mass of the car is 1,000 kg. The car’s engine produces 1,000 N of thrust against the force of friction of the road. What is the coefficient of friction of the road?
(A) 0.1
(B) 0.2
(C) 0.3
(D) 0.4
(E) 0.5
114. A 1,000-kg car is traveling at 30 m/s. The driver applies the brakes, which exert a constant 9,000 N of force. The car uniformly decelerates to a complete stop. How far does the car travel before coming to a complete stop?
(A) 2 m
(B) 50 m
(C) 100 m
(D) 200 m
(E) 450 m
115. This position–time graph is typical of which type of motion?
(A) Motion of an object with an increasing net force acting upon it
(B) Motion with zero velocity
(C) Motion with a constant positive net force acting upon it
(D) Motion of an object with no net force acting upon it
(E) Motion of an object with negative net force acting upon it
116. A 70-kg runner accelerates uniformly from rest to 10 m/s in 0.5 s. What is the net force acting upon him?
(A) −7,000 N
(B) −1,400 N
(C) 0 N
(D) 1,400 N
(E) 7,000 N
117. A 50-kg ice skater comes to a complete stop by applying a force of friction of 1,000 N opposite her direction of motion. The deceleration is uniform over a period of 0.5 s. What was her initial velocity?
(A) 5 m/s
(B) 10 m/s
(C) 20 m/s
(D) −20 m/s
(E) −10 m/s
118. The acceleration–time graph of an object’s motion is shown in this figure. At what time will the forces acting on it be balanced?
(A) 0 s
(B) 1 s
(C) 2 s
(D) 3 s
(E) 4 s
119. An archer stands on a castle wall that is 45 m high. He shoots an arrow with a velocity of 10.0 m/s at an angle of 45° relative to the horizontal. The arrow is shot into a constant headwind that exerts a force of 0.05 N on the arrow. The arrow has a mass of 0.050 kg.
(a) Determine the magnitude of the horizontal and vertical components of the arrow’s initial velocity.
(b) Determine how much time it takes for the arrow to reach the ground.
(c) Determine the maximum range of the arrow into the wind.
(d) How much farther would the arrow go if the wind wasn’t blowing?
120. A 10-kg box slides down a plane inclined at an angle (θ = 30°). The plane has a coefficient of friction (μ = 0.1). The box starts from rest and slides down the plane for 2.0 s.
(a) Draw a free-body diagram of this situation and label all the forces on the box.
(b) Calculate the force of friction on the box.
(c) Calculate the acceleration of the box.
(d) Calculate the final velocity of the box.
(e) Calculate the distance that the box moves down the plane in the given time interval.