Physics kinematic

Question

1. as the race begins you accelerate at a constant rate of 0.49 m/s^2 . the finish line is 100m away from the starting line, what was your velocity as you crossed the finish line.



for this question the net force on you is 100N upwards after bouncing on a trampoline, using mass (your weight (150 pounds)/2) get your mass in kg



now that you have mass what is your acceleration upwards based on the net force and your mass?

Answer 1

1.

We will use the identities

v = a t (1)

s = a t² / 2 (2)

where

t is the time to run the race (unknown, but calculated below)

a = 0.49 m/s² is the given acceleration

v is the velocity with which you cross the finish line

s = 100 m is the distance run

t = sqrt(2s/a) // solving for t from identify (2)

t = sqrt(200/0.49) = 20.2 s // plugging in given quantities and evaluating

v = 0.49 * 20.2 = 9.9 m/s // plugging given acceleration and calculated time into identity (1)

2.

We use Newton's second law

F = a m

where

F = 100N is the given force

a is the acceleration to be computed

m = 75kg is the given mass

a = F / m = 100/75 = 1.33 m/s²