brakes are applied to a moving truck to produce retardation of 5m+s2 if the time taken between application of - Science - Motion

Question

brakes are applied to a moving truck to produce retardation of
5m+s2 if the time taken between application of brakes and the truck
to stop is 2s, calculate the distance travelled by the truck during
this time

Tejal · Accepted Answer

The distance covered by the truck will be 10 m as,
v = final velocity = 0 ms-1 as it comes to rest
u = initial velocity = ?
t = time = 2 sec
a = acceleration = -5 ms-2 (it is negative as it is in
the opposite direction)
s = distance = ? which is what we have to find

Using the equations of motion,
v = u + at
0 = u + (-5)(2)
0 = u + (-10)
0 = u - 10
Bringing 10 to the LHS
​0 + 10 = u
u = 10 ms-1

By the second equation of motion
s = ut + 1/2at2
s = (10)(2) + 1/2(-5)(2)2
s = 20 + 1/2(-5)(2)(2)
s = 20 + (-5)(2)
s = 20 + (-10)
s = 20 - 10
s = 10 m

brakes are applied to a moving truck to produce retardation of 5m+s2. if the time taken between application of brakes and the truck to stop is 2s, calculate the distance travelled by the truck during this time.