QUESTION 16
A constant horizontal force is exerted on a cart that is initially at rest on an air track. Friction between the cart and track is negligible. The force acts for
short time interval and gives a cart certain final speed. To reach the same final speed with a force that is only half as big, the force must be exerted on
the cart for a time interval ______ that for the shorter force.
a. Four times as long as
b. Twice as long as
c. equal to
d. Half as long as
QUESTION 17
A large truck breaks down out on the road and receives a push back into town by a small compact car. For the car and truck, which is the correct
statement of the situation?
a. The truck moves forward because the car pushes slightly harder on the truck than the truck pushes back on the car.
b. The car cannot move the truck because the truck pushes back on the car with the same force with which the car pushes on the truck.
c. The car can only push the truck forward if the truck weighs less than the car.
d. The car can only move the truck if the car's traction force (i.e. the force generated by the wheels and the road) is greater than the force with which
the truck pushes back on the car.
