The washer, weighing 0.2 kg, after being hit with a club, began to slide on the ice at a speed of 20 m / sec.

| August 11, 2021 | education

The washer, weighing 0.2 kg, after being hit with a club, began to slide on the ice at a speed of 20 m / sec. The friction force of the washer on ice is 0.04 N. Determine the acceleration of the puck as it slides on ice. How long will it take to stop?

Using Newton’s second law F = ma, we find the acceleration a of a washer of mass m when sliding on ice under the action of the friction force Ffr:

a = Ftr / m = 0.04 / 0.2 = 0.2 m / s2.

The speed v of the washer, having an initial speed of v0 = 20 m / s, with an equally slow motion with an acceleration of a = 0.2 m / s2, changes in accordance with the formula v = v0 – at, where t is time. At the moment of stopping, the speed v of the washer is 0. That is

0 = 20 – 0.2t, whence

t = 20 / 0.2 = 100 s.

Answer: a = 0.2 m / s2, t = 100 s.



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