PHYS 3.4 Homework

A boy steps off the end of a 3.0 m high dive and drops to the water below. What is his speed when he hits the water? (Use the equation v_f² = v_i² + 2aΔx)

• 7.67 m/s

• 8.23 m/s

• 6.12 m/s

• 10.02 m/s

A boy steps off the end of a 10.0 m high dive and drops to the water below. What is his speed (in m/s) when he hits the water?

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

One fine summer day, a group of students were jumping from a railroad bridge into the Osage River. They stepped off the bridge when they "jumped", and they hit the water 1.5 s later. How high (in meters) was the bridge?

Two rocks with different weights are dropped on the surface of the Moon. How does the acceleration of the heavier rock compare to that of the lighter rock?

• they are equal

• the heavier rock accelerates more

• the lighter rock accelerates more

• they fall at a constant rate

Tags

NGSS.HS-PS2-1

Why is a person doing a cannonball dive an example of free fall while a person descending to Earth on a parachute is not?

• gravity does not affect a person on a parachute

• gravity is less for a person on a parachute

• free fall is motion due only to the force of gravity

At the end of a baseball game Zoe drops her glove to the ground. Mickey tosses his glove into the air. While the gloves are still in the air, the acceleration of Zoe's glove is

• greater than the acceleration of Mickey's glove

• less than the acceleration of Mickey's glove

• equal to the acceleration of Mickey's glove

Tags

NGSS.HS-PS2-1

A girl on a trampoline bounces straight upward with an initial velocity of 4.5 m/s. What is the girl's velocity when she returns to the trampoline?

• 4.5 m/s

• greater than 4.5 m/s

• less than 4.5 m/s

Seagulls are often observed dropping clams and other shellfish from a height onto rocks below, as a means of opening the shells. If a seagull drops a shell from rest from a height of 14 m, how fast (in m/s) is the shell moving when it hits the rocks?

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

A volcano launches a lava bomb straight upward with an initial velocity of 28 m/s. Taking upward to be the positive direction, find the velocity (in m/s) of the lava bomb at 2.0 s after it is launched.

Tags

NGSS.HS-PS2-1

A volcano launches a lava bomb straight upward with an initial velocity of 28 m/s. Taking upward to be the positive direction, how long (in sec) does it take for the lava bomb to reach its highest point?