Question

a car having mass 700kg is moving at a a speed of 90km/h. on applying brakes its speed is reduced to 36km/h in 10s. calculate the force applied by the brakes.

Answer 1

u-36km/h
v-90km/h
t-10s
m-700kg
change initial and final velocity in m/s.
than a- 1.5m/s
F-m*a
F -700*1.5
F -1050

Answer 2

hello friend
pls find ur answer below

m= 700 kg
u= 90 km/hr = 90 * 5/ 18 m/s = 25 m/s 
v = 36 km/hr = 30 * 5/18 m/s = 10 m/s
t = 10s 
a = ?
F = ?
a= (v-u) /t
a = (10 - 25) / 10
a = -15/10 = -1.5 m/s ²
negative sign means car is retarding 
we know that Force = mass * acceleration
so, 700 * ( - 1.5) 
F = -1050 N 

therefore ∴ the force applied by the brakes is 1050 N in the opposite direction .

hope it helps =)
pls thumbs up