BackA 1000 kg weather rocket is launched straight up. The rocket motor provides a constant acceleration for 16 s, then the motor stops. The rocket altitude 20 s after launch is 5100 m. You can ignore any effects of air resistance. What was the rocket's acceleration during the first 16 s?
A rock is tossed straight up from ground level with a speed of 20 m/s. When it returns, it falls into a hole 10 m deep. What is the rock's speed as it hits the bottom of the hole?
A lead ball is dropped into a lake from a diving board 5.0 m above the water. After entering the water, it sinks to the bottom with a constant velocity equal to the velocity with which it hit the water. The ball reaches the bottom 3.0 s after it is released. How deep is the lake?
As a science project, you drop a watermelon off the top of the Empire State Building, 320 m above the sidewalk. It so happens that Superman flies by at the instant you release the watermelon. Superman is headed straight down with a speed of 35 m/s. How fast is the watermelon going when it passes Superman?
Ball bearings are made by letting spherical drops of molten metal fall inside a tall tower—called a shot tower—and solidify as they fall. What is the bearing's impact velocity?
Ball bearings are made by letting spherical drops of molten metal fall inside a tall tower—called a shot tower—and solidify as they fall. If a bearing needs 4.0 s to solidify enough for impact, how high must the tower be?
A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the side of the rocket. The bolt hits the ground 6.0 s later. What was the rocket's acceleration?
A hot-air balloonist, rising vertically with a constant velocity of magnitude m/s, releases a sandbag at an instant when the balloon is m above the ground (Fig. E). After the sandbag is released, it is in free fall. What is the greatest height above the ground that the sandbag reaches?
A hot-air balloonist, rising vertically with a constant velocity of magnitude m/s, releases a sandbag at an instant when the balloon is m above the ground (Fig. E). After the sandbag is released, it is in free fall. Compute the position and velocity of the sandbag at s and s after its release.
A lunar lander is making its descent to Moon Base I (Fig. E). The lander descends slowly under the retro-thrust of its descent engine. The engine is cut off when the lander is m above the surface and has a downward speed of m/s. With the engine off, the lander is in free fall. What is the speed of the lander just before it touches the surface? The acceleration due to gravity on the moon is m/s.
You throw a glob of putty straight up toward the ceiling, which is m above the point where the putty leaves your hand. The initial speed of the putty as it leaves your hand is m/s. What is the speed of the putty just before it strikes the ceiling?
A small rock is thrown vertically upward with a speed of m/s from the edge of the roof of a -m-tall building. The rock doesn't hit the building on its way back down and lands on the street below. Ignore air resistance. How much time elapses from when the rock is thrown until it hits the street?
A small rock is thrown vertically upward with a speed of m/s from the edge of the roof of a -m-tall building. The rock doesn't hit the building on its way back down and lands on the street below. Ignore air resistance. What is the speed of the rock just before it hits the street?
A -kg rock is dropped from rest on the earth and reaches the ground in s. When it is dropped from the same height on Saturn's satellite Enceladus, the rock reaches the ground in s. What is the acceleration due to gravity on Enceladus?
A brick is dropped (zero initial speed) from the roof of a building. The brick strikes the ground in s. You may ignore air resistance, so the brick is in free fall. What is the magnitude of the brick's velocity just before it reaches the ground?