Q8 of 35 Page 143

A constant force acts on an object of mass 5kg for a duration of 2s. It increases the object velocity from 3m/s to 7m/s. Find the magnitude of the force applied. Now if the force were applied for a duration of 5s, what would be the final velocity of the object?

Using the first equation of motion

v = u + at


7m/s = 3m/s + a(2s)


4 = 2a


2m/s2 = a


And, as


Force = Mass × Acceleration


= 5kg × 2m/s2


= 10N


Final velocity after 5s,


Using First Equation of Motion


v = u + at


v = 3 + 2(5)


v = 13m/s


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