Asked by chibwe

A car of mass 1200kg travelling at 72km/h was brought to rest in 4 seconds.
1. what is this period in m/s?
2. find;
a. the deceleration of the car.
b. the force that caused the car to come to rest.
c.the distance it travelled during its deceleration.
Answered by Steve
1 km/hr = 20 m/s

periods are not measured in m/s

a = (-20m/s)/(4s) = -5 m/s^2

F = ma

s = 1/2 at^2

...
Answered by Henry
1. 72km/h = 72000m/3600s = 20 m/s.
2a. V2 = V1 + a*t.
0 = 20 + a*4,
a = -5 m/s^2 = deceleration.

2b. F = M*a = 1200 * (-5) = -6000 N.
The negative sign means the force opposes the motion.

2c. V2^2 = V1^2 + 2a*d.
0 = 20 - 10d,
d = 2m.


Answered by Henry
2c. Correction:
0 = 20^2 - 10d,
d = 40 m.
Answered by raymond
12
Answered by iaymond mulenga
what is physics
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