A block is supported on a compressed spring, which projects the block straight up in the air at velocity 
. The spring and ledge it sits on then retract. You can win a prize by hitting the block with a ball. When should you throw the ball and in what direction to be sure the ball hits the block? (Assume the ball can reach the block before the block reaches the ground and that the ball is thrown from a height equal to the release position of the block.)
A. At the instant when the block leaves the spring, directed at the block
B. At the instant when the block leaves the spring, directed at the spring
C. At the instant when the block is at the highest point, directed at the block
D. At the instant when the block is at the highest point, directed at the spring
E. When the block is back at the spring's original position, directed at that position
Answer: C
You might also like to view...
Rotational Kinetic Energy: A uniform solid disk is released from rest and rolls without slipping down an inclined plane that makes an angle of 25° with the horizontal. What is the forward speed of the disk after it has rolled 3.0 m, measured along the plane?
A. 2.0 m/s B. 3.5 m/s C. 4.1 m/s D. 5.7 m/s E. 6.3 m/s
A car travels at 17m/s without skidding around a 35m radius unbanked curve. What is the minimum value of the static friction coefficient between the tires and the road?
A. 0.84 B. 0.050 C. 0.0014 D. 0.024
What evidence is there that supernovae really have occurred?
A) Crab Nebula B) supernova remnants C) existence of heavy radioactive elements in nature D) observations of the actual explosions E) All of the above.
A pilot punches the throttle lever forward, changing his speed from 0 m/s to 40 m/s in 7 seconds. The acceleration of the racecar is _________
Fill in the blank(s) with correct word