# A person pushes a mouse with a mass 500 g across a table for 20 cm. The initial velocity of the mouse is 0.1m/s and the final velocity is 0.7m/s. There is a constant frictional force of 0.5 N. What...

A person pushes a mouse with a mass 500 g across a table for 20 cm. The initial velocity of the mouse is 0.1m/s and the final velocity is 0.7m/s. There is a constant frictional force of 0.5 N. What is the force applied by the person.

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### 1 Answer

The initial velocity of the mouse when it is pushed is 0.1 m/s and the final velocity is 0.7 m/s. The increase in velocity is over a distance of 20 cm or 0.2 m.

The acceleration required for this is given by the relation v^2 - u^2 = 2*a*s where v = 0.7, u = 0.1 and s = 0.2

=> a = (0.7^2 - 0.1^2)/(2*0.2)

=> a = 1.2 m/s^2

As the mass of the mouse is 0.5 kg, the force required is 1.2*0.5 = 0.6 N

There is also a constant force of friction equal to 0.5 N.

This gives the force that has to be applied as 0.6 + 0.5 = 1.1 N

The person is pushing the mouse with a constant force of 1.1 N.