Question

You are sitting in a sled, at rest on a pond covered with nice, thick, frictionless ice. Your own mass of is 84 kg, and the mass of the sled when empty is 11.5 kg. (a) From shore, someone throws a baseball of mass 0.11 kg to you, and you catch it; the horizontal component of the ball’s velocity is 32.6 m/s. What will be the sled’s (and your) speed with respect to the surface of the pond after you catch the ball? Note that your answer should be in centimeters per second. (b) Different situation: suppose you are in the sled and it’s already moving to the west, at a speed of 1.1 cm/s. From the southern shore, your friend again throws a baseball of mass 0.11 kg, which you catch as it’s traveling northward with a horizontal velocity component of 32.6 m/s. In this case, what will be the sled’s (and your) speed after catching the ball? (c) Once again, suppose you start at rest on the sled out on the pond. Suddenly, you jump off of the sled, after which the empty sled is traveling at a speed of 2.6 m/s. (Note that this is now in meters per second.) What will be your speed on the ice after jumping off? (Note: this will be the same as the horizontal component of your velocity just as you jump.) (d) That empty sled is still moving now at 2.6 m/s. A parachutist of mass 66 kg suddenly drifts straight vertically down from a helicopter, landing on the sled. What will be the sled’s speed (including the parachutist) after he lands?

Answer 1