10. a ball of a mass m at the end of a string is swung in a horizontal circular path if radius R at constant speed V. which combination of changed would require the greatest increase in the centripetal force acting on the ball ?(1) 2V and 2R (2) 2V and 1/2R (3) 0.5R and 2V(4) 0.5V and 0.5V
11. an airplane is moving with a constant velovity in level flight. compare the magnitude of the forward force provided by the engines to the magnitude of the backward frictional drag force.
Explain!