Mass of the car (m) = 200 kg Initial speed (u) = 36 km/h = 10 m/s Final velocity (v) = 0
Distance covered (S) = 10 m
v2 - u2 = 2aS 0 - 100 = 2 x a x 10 - 100 = 20 aa = - 100/20 = -5 m/s2
F = ma = 200 x 5 = -1000 N
Retarding force = 1000 N
Let force acting on the object when the mass is doubled be equal to F1 i.e., Mass (m1) = 2 m
Acceleration produced = a1 F1 = 2m x a1 Given F = F1
a1 = a/2
i.e., acceleration is reduced to half.
a = (v-u)/t = (4.2 - 1.8)/1.2= 2 m/s2
As the same force acts for the next two seconds the acceleration produced will be the same. The final
velocity in the first case will now become the initial velocity.
We have to calculate the final velocity at end of 2 seconds.
Acceleration (a) = 2 m/s2 Intial velocity (u) = 4.2 m/s, t = 2 s Final velocity (v) = ?
[First equation of motion]
v = u + at [First equation of motion]
Post related to 9th Force and law of Motion.