Question

Plz answer fast as u can??​

Answer 1

SOLUTION

Given =》

Mass of motor car = 1200kg

Uniform velocity = 90km/h

To Find =》

Acceleration and change in momentum

And calculate the magnitude of force required ??

Explanation =》

Mass of car, m = 1200 kg

Initial velocity of car, u = 90 km/h

= 90×1000m/60×60s

= 25m/s

Final velocity of car , v= 18km/h

= 18×1000m/ 60×60s

= 5m/s

Time Taken, t= 4s

As per definition,

Acceleration, a= v-u/t

= 5-25/4

= -20/4

= -5m/s²

Negative acceleration means that the car in under retardation

Change in momentum = m×(v-u)

= 1200×(5-25)

= 1200×(-20)

= -24000kg m/s

The negative change in momentum means that the car is slowing down.

And,

Magnitude of the force = m×a

= 1200×(-5)

= -6000kg m/s²

= -6000N

The negative sign indicates that the external force is acting in the direction opposite to the direction of motion.

Answer 2

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