While playing with her 5 year old cousin, a Physics 135 student pushed him forward on his scooter. She pushes with a force of 50 Newtons for 3.5 seconds.
If the boy and the scooter together have a mass of 30 kg, what is their final velocity?

a.2.06 m/s
b.12.54 m/s
c.5.83 m/s
d.0.99 m/s

10.2 m/s^2.

Explanation:

Momentum = Force x time

F x t = m*vf - m*vi

Initially at rest, vi = 0 m/s

v = F*t/m

= 50 * 3.5/30

= 5.83 m/s

acceleration = velocity/time

= 5.83/3.5

= 1.67 m/s^2

Using,

S = vi*t + 1/2 at^2

S = 1/2 * 1.67 * 3.5 * 3.5

= 10.21 m

i will answer your question if you answer mine

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s