# 1) a rocket moves upward, starting from rest with an acceleration of

1) A rocket moves upward, starting from rest with an acceleration of 29.4 m/s2 for 8.00 s. It runs out of fuel at the end of the 8.00 s but does not stop. How high does it rise above the ground?

m

2) Two students are on a balcony 16.6 m above the street. One student throws a ball vertically downward at 16.7 m/s. At the same instant, the other student throws a ball vertically upward at the same speed. The second ball just misses the balcony on the way down. (Assume the positive direction is upward.)

(a) What is the difference in the time the balls spend in the air?

s

(b) What is the velocity of each ball as it strikes the ground?

ball thrown downward

m/s

ball thrown upward

m/s

(c) How far apart are the balls 0.800 s after they are thrown?

m

3) A small fish is dropped by a pelican that is rising steadily at 0.55 m/s. (Assume the positive direction is upward.)

(a) After 3.0 s, what is the velocity of the fish?

m/s

(b) How far below the pelican is the fish after 3.0 s?

m

4) A parachutist descending at a speed of 25.0 m/s loses a shoe at an altitude of 40.0 m. (Assume the positive direction is upward.)

(a) When does the shoe reach the ground?

s

(b) What is the velocity of the shoe just before it hits the ground?

m/s

5) A mountain climber stands at the top of a 50.0 m cliff hanging over a calm pool of water. The climber throws two stones vertically 1.1 s apart and observes that they cause a single splash when they hit the water. The first stone has an initial velocity of 2 m/s. (Assume the positive direction is upward.)

(a) How long after release of the first stone will the two stones hit the water?

s

(b) What is the initial velocity of the second stone when it is thrown?

m/s

(c) What will the velocity of each stone be at the instant both stones hit the water?

first stone

m/s

second stone

m/s

6) A model rocket is launched straight upward with an initial speed of 60.0 m/s. It accelerates with a constant upward acceleration of 6.0 m/s2 until its engines stop at an altitude of 150 m.

(a) What is the maximum height reached by the rocket?

m

(b) How long into the flight does the rocket reach maximum height?

s

(c) How long is the rocket in the air?

s