Question

A skydiver slows down from 65 m/s to 5 m/s by opening the parachute. If this

takes 0.75 seconds, what is the skydiver's acceleration?
A. 45 m/s2 up
B. 80 m/s2 up
C. 45 m/s2 down
D. 80 m/s2 down

Answer 1

D. -80m/s^2

Step-by-step explanation:

V = u + at

5 = 65 + a (0.75)

0.75a = -60

a = -60/0.75

a = -80m/s^2

Therefore, is decelerating at 80m/s^2

Answer 2

`\boxed {\boxed {\sf D. \ 80 \ m/s^2 \ down}}`

Step-by-step explanation:

We are asked to find the acceleration of a skydiver. Acceleration is the change in velocity over the change in time, so the formula for calculating acceleration is:

`a= (v_f-v_i)/(t)`

The skydiver was initially traveling 65 meters per second, then he slowed down to a final velocity of 5 meters per second. He slowed down in 0.75 seconds.

`\bullet \ v_f = 5 \ m/s \\\bullet \ v_i= 65 \ m/s \\\bullet \ t= 0.75 \ s`

Substitute the values into the formula.

`a= ( 5 \ m/s - 65 \ m/s)/(0.75 \ s)`

Solve the numerator.

`a= (-60 \ m/s)/(0.75 \ s)`

Divide.

`a= -80 \ m/s^2`

The acceleration of the skydiver is -80 meters per second squared or 80 meters per second squared down. The skydiver is slowing down or decelerating, so the acceleration is negative or down.