Question

A 640-N hunter gets a rope around a 3200-N polar bear. They are stationary, 20m apart, on frictionless level ice. When the hunter pulls the polar bear to him, the polar bear will move: A. 1:0m B. 3:3m C. 10m D. 12m E. 17m

Answer 1

When the hunter pulls the polar bear to him, the polar bear will move 3.3 meters.

Step-by-step explanation:

It is given that, a 640-N hunter gets a rope around a 3200-N polar bear. They are stationary, 20 m apart, on friction less level ice.

The given system is an isolated system which is initially at rest and they both will meet at the center of mass. Then finding the center of mass of the system as :

`X_(com)=(m_1x_1+m_2x_2)/(m_1+m_2)`

Multiplying "g" to the numerator and denominator both as :

`X_(com)=(gm_1x_1+m_2x_2g)/(m_1g+m_2g)`

`X_(com)=(640(0)+3200* 20)/(640+3200)=16.67\ m`

i.e. 640 N hunter moves at a distance of 16.67 meters and when the hunter pulls the polar bear to him, the polar bear will move, 20 m - 16.67 m = 3.3 meters. Hence, this is the required solution.