During a circus act, a performer thrills the crowd by catching a cannon ball shot at him. The cannon ball has a mass of m1 = 7.5 kg and the horizontal component of its velocity is v = 8.85 m/s when the performer, of mass m2 = 61.5 kg, catches it.

If the performer is on nearly frictionless roller skates, what is his recoil velocity?

Explanation:

We shall apply law of conservation of momentum .

total Initial momentum =

7.5 x 8.85 = 66.375 kg m / s

total mass = 7.5 + 61.5 = 69 kg , common velocity of ball and performer be v

Total momentum = 69 v

69 v  = 66.375

v = 66.375 / 69

= .962 m /s .

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1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

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