Question

a vehicle of mass 20kg is moving with a velocity of 4ms,find the magnitude of the force that is to br applied on the vehicle so that the vehicle have a velocity of 1ms after travelling a distance of 20m.

Answer 1

Answer on Question #61262-Physics-Mechanics-Relativity

A vehicle of mass 20kg is moving with a velocity of 4ms, find the magnitude of the force that is to be applied on the vehicle so that the vehicle have a velocity of 1ms after travelling a distance of 20m.

Solution

We use kinematic equation for deceleration:

$$v _ {i} ^ {2} - v _ {f} ^ {2} = 2 a d \rightarrow a = \frac {v _ {i} ^ {2} - v _ {f} ^ {2}}{2 d}$$

From the Second Newton's law:

$$F = m a = m \frac {v _ {i} ^ {2} - v _ {f} ^ {2}}{2 d} = 2 0 \frac {4 ^ {2} - 1 ^ {2}}{2 (2 0)} = 7. 5 N.$$

Answer: 7.5 N.

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