Question

A particle moving in a straight line with uniform deceleration has a velocity of 40m/s at point p, 20m/s at point q and comes to rest at point R where QR=50m .Calculate the 1.Distance PQ 2.Time taken to cover PQ 3.Time taken to cover PR

solve for me pls
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Answer 1

Answer: 150 metres/5 seconds/5 seconds

Step-by-step explanation:

Find the acceleration/deceleration
v^2 = u^2 + 2as; v=final velocity u=initial velocity a=acceleration s=distance
0^2 = 20^2 + 2*a*50
a = -4 m/s Therefore, the particle is decelerating at 4 m/s
From there, we can work out PQ
Using the same equation, we get that
20^2 = 40^2 + 2*-4*s
s = 150 m so Distance PQ is 150 metres
Finding the time taken to cover PQ and PR uses a different equation
v = u + at; t = time and everything else is the same
20 = 40 - 4t
t = 5 s so Time taken to cover PQ is 5 seconds
0 = 20 - 4t
t = 5 s so Time taken to cover PR is also 5 seconds