MARKING BRAINLIEST AND I NEED WORK SHOWN ! i’m a junior in high school Free Fall Practice Problems

1. A baseball is popped straight up in the air at a velocity of 42.0 m/s.

What time does it spend in the air before reaching the same

elevation from which it was popped up?

2. A golf ball is dropped from a cliff and strikes the ground with a

downward velocity of 34.0 m/s. How high is the cliff?

3. An air rocket is launched straight upwards at 27.0 m/s. What is its

velocity at time t=4.80 s?

4. A giant lizard jumps straight upwards from the ground at 4.30 m/s.

To what height does the lizard rise before going back down again?

5. A person falls from a bridge that is 18.0 m above the water. What

is the velocity of impact with the water?

(1) t = 4.29 s

(2) h = 58.98 m

(3) v = 20.04 m/s (downward)

(4) h = 0.94 m

(5) v = 18.78 m/s

Explanation:

Assumption:

(1)

initial velocity of the baseball, u = 42.0 m/s

final velocity of the ball, v = 0

time of flight is given by;

v = u -gt

gt = u

t = u / g

t = 42 /9.8

t = 4.29 s

(2)

Given;

initial velocity of the golf, u = 0

final velocity of the golf, v = 34 m/s

the height of the cliff is given by;

v² = u² + 2gh

v² = 0 + 2gh

h = v²/2g

h = (34)²/(2x9.8)

h = 58.98 m

(3)

Given;

initial velocity of the rocket, u = 27 m/s

time of motion, t = 4.8s

final velocity, v = ?

v = u + gt

v = 27 + (-9.8 x 4.8)

v = 27 - 47.04

v = -20.04 m/s (the negative sign indicates downward motion of the rocket after 4.8 s)

(4)

Given;

initial velocity of the lizard, u = 4.3 m/s

final velocity of the lizard at maximum height, v = 0

the height rose by the lizard is given by;

v² = u² + 2(-g)h

0 = u² - 2gh

2gh = u²

h = u² / 2g

h = (4.3)²/(2 x 9.8)

h = 0.94 m

(5)

Given;

initial velocity of the person on the bridge, u = 0

height of the bridge, h = 18 m

final velocity of the person is the velocity at impact, v = ?

v² = u² + 2gh

v² = 0 + 2gh

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 18)

v = 18.78 m/s

ok

explanation: