Question

1. A skateboarder with a mass of 70 kg is riding a skateboard on a smooth, frictionless surface. The skateboarder applies a constant force of 150 N in the positive x-direction by pushing against the ground. (a) Calculate the acceleration of the skateboarder and the skateboard. (b) If the skateboarder starts from rest, how long does it take to reach a speed of 10 m/s? (c) Once the skateboarder reaches a speed of 10 m/s, they encounter a slight incline with a constant net resistance force of 30 N opposing their motion. Determine the time it takes for the skateboarder to come to a stop.

Answer 1

Step-by-step explanation:

a) F = ma

150 = 70 x a

a = 150/70

a = 2.14 m/
`s^(2)`

b) v = u + at

v = at

t = 10/2.15

t = 4.65 s

c) F = ma

- 30 = 70 a

a = -30/70

a = - 0.43 m/
`s^(2)`

v = u + at

t = -u/a

t = -10/-0.43

t = 23.3 s