A 211 student, who is initially at rest, wants to catch a Frisbee. When the Frisbee passes over her head it is moving at a speed of 4 m/s, and this is when she starts to run in the same direction as the Frisbee, accelerating at a rate of 1 m/s2. The Frisbee is decelerating at a rate of 1.5 m/s2. (You may neglect the vertical motion of the Frisbee).
How long Δt will it take the student to catch the Frisbee?
(a) Δt = 3.20 s (b) Δt = 4.15 s (c) Δt = 5.32 s (d) Δt = 6.18 s (e) Δt = 6.97 s
(a) (b) (c)
(a) Its acceleration must be in the same direction as the force. (b) Its velocity must be in the same direction as the force. (c) Its velocity is constant and is in the same direction as the force.
What is the tallest wall the player's ball can clear 120 m away?
(a) 2.98 m (b) 3.22 m (c) 5.06 m (d) 5.74 m (e) 6.28 m
Two blocks, of mass M1 = 8 kg and M2 = 3 kg are in contact with each other on a frictionless floor. A horizontal force F = 72 newtons is applied to block M1 as shown.
What is the force F1on2 of the block of mass M1 on the block of mass M2?
(a) F1on2 = 0.0 N (b) F1on2 = 5.1 N (c) F1on2 = 19.6 N (d) F1on2 = 51.3 N (e) F1on2 = 72.0 N
(a) decrease. (b) stay the same. (c) increase.
The magnitude of the total force acting on M2 is now
(a) bigger than it was without friction. (b) smaller than it was without friction. (c) the same as it was without friction.
Two stones are thrown simultaneously from a height of 500 m. The first stone is thrown vertically downward at a speed of 10 m/s, while the second stone is thrown vertically upward at a speed of 10 m/s.
Immediately after the two stones are thrown, the difference in their speeds ( |vdown| - |vup| ) will
(a) increase with time. (b) decrease with time. (c) stay the same.
(a) increase. (b) decrease. (c) stay the same.
(a) Δt = 2.04 s (b) Δt = 3.02 s (c) Δt = 4.62 s (d) Δt = 5.38 s (e) Δt = 6.02 s
A block of mass M = 2 kg is on a stationary inclined plane inclined with an angle θ = 30°. A horizontal rope is attached to the block and is pulled to the right with tension T. The tension remains horizontal even in the event that the block moves down the plane. The coefficient of static friction between the block and the inclined plane is μs = 0.7 and the coefficient of kinetic friction is μk = 0.5 .
Which of the following is the correct free-body diagram for the block?
(a) Tmax = 0.18 N (b) Tmax = 0.37 N (c) Tmax = 0.63 N (d) Tmax = 1.71 N (e) The block remains held in place with static friction for all values of T.
A projectile is fired from a submarine traveling horizontally at 20 m/s with respect to the water as shown in the figure below. According to an observer on the submarine, the projectile is fired at 45° with an initial velocity of 60 m/s. After firing the projectile, the submarine continues to travel at 20 m/s.
According to an observer watching from a boat that is stationary with respect to the water, what will be the angle θ that the projectile makes with respect to the horizontal when it is launched?
(a) θ = 30.9° (b) θ = 34.2° (c) θ = 45° (d) θ = 62.1° (e) θ = 71.6°
(a) 0 m/s (b) 22.4 m/s in the opposite direction the submarine is moving (c) 22.4 m/s in the same direction the submarine is moving (d) 43.7 m/s in the opposite direction the submarine is moving (e) 43.7 m/s in the same direction the submarine is moving
Block m1 (5 kg) is hanging over the edge of a frictionless table and is attached to a block m2 (20 kg) by a massless string that runs over a frictionless, massless pulley as shown in the figure. Block m2 is also attached to a wall by an ideal, massless spring with a spring constant of 130 N/m that has a relaxed length of X0.
By how much is the spring compressed or stretched relative to its relaxed length X0 if the system is in equilibrium?
(a) The spring is compressed by 0.377 meters. (b) The spring is compressed by 0.141 meters. (c) The spring is neither compressed nor stretched. (d) The spring is stretched by 0.141 meters. (e) The spring is stretched by 0.377 meters.
(a) a = 0.00 m/s2 (b) a = 3.52 m/s2 (c) a = 4.18 m/s2 (d) a = 5.92 m/s2 (e) a = 9.81 m/s2
A student twirls a tennis ball of mass m at the end of a string of length l in a vertical plane.
What is the minimum speed, v, required to just keep the string taut when the ball is at the top of its travel?
(a) (b) (c) (d) (e)
(a) the horizontal component of the velocity remains constant and the vertical component increases in magnitude. (b) the horizontal and vertical components of the velocity remain constant. (c) the horizontal component of the velocity decreases in magnitude and the vertical component remains constant.
(a) the ball's weight and the centripetal force in the vertical direction. (b) the ball's weight. (c) There are no forces on the ball after the string is cut.
A satellite is put into a uniform circular orbit around the earth. The radius of the satellite's orbit is Rs = 4.2 × 107 m (measured from the center of the earth). The satellite has a mass of 45 kg.
At the instant shown above, the direction of the satellite's acceleration vector is.
(a) 2.3 km/s (b) 3.1 km/s (c) 5.7 km/s (d) 6.2 km/s (e) 9.8 km/s