Question

A car is held motionless off the ground by a hovering helicopter. If the car's mass is 1500kg, what is the force on the car due to gravity? A. 153 N B. 1470 N C. 1500 N D. 14,700 N

Answer 1

Answer:

option D

Explanation:

In this case, we have a helicopter lifting a car. The car has a mass of 1500 kg and we want to know the force that the car is feeling due to gravity.

In this case, as the car is being lifted by the helicopter, we can say that the force of the helicopter is equivalent to the force of gravity that the car is feeling.

Using the second law of Newton we have:

F = m.a

In this case, the force that gravity exerts, is the weight and is calculated with the same expression but using the gravity acceleration of Earth whic is 9.81 m/s², therefore:

W = m.g

Now that we have mass and gravity, we can calculate the force of gravity so:

W = 1500 * 9.81

W = 14,715 N

This is close to the value of option D, so the answer would be that.

Answer 2

Force of the helicopter is equivalent to weight for this case. Weight is calculated by multiplying the mass of the object and the acceleration. For this case, the acceleration would be the acceleration due to gravity which is equal to 9.81 m/s^2. We calculate as follows:

W = mg 
W = 1500 kg ( 9.81 m/s^2 )

W = 14715 N