Question

A car is traveling at a steady 73 km/h in a 50 km/h zone. A police motorcycle takes off at the instant the car passes it, accelerating at a steady 7.0 m/s2 .a) How much time elapses before the motorcycle is moving as fast as the car?Express your answer to two significant figures and include the appropriate units.b) How far is the motorcycle from the car when it reaches this speed?Express your answer to two significant figures and include the appropriate units.

Answer 1

Answer:

29 m

Explanation:

given,

speed of the car = 73 Km/hr

                           = 73 x 0.278 m/s  = 20.3 m/s

Time elapses before the motorcycle is moving as fast as the car

using equation of motion

v = u + at

initial speed = 0 m/s

20.3= 0 + 7 x t

t = 2.9 s

b) distance traveled by the car in that time

  d = s x t

  d = 20.3 x 2.9 = 58.87 m

 distance traveled by the police

$s = ut + \dfrac{1}{2} a t^2$

$s = 0 + \dfrac{1}{2}\times 7\times 2.9^2$

s = 29.435 m

distance car is ahead = 58.57 - 29.44 = 29.13

                                    = 29 m