Please answer the below question on momentum. Please explain working if possible 1. A sports car moving is going at 55 m/s and has mass of 1,200 Kg. On the other hand, there is a giant dump truck with mass of 7,800 Kg moving at 14 m/s. Of the two which one has greater momentum? Show calculations. What is the difference (in momentum) between the two? If there is a new car with same weight but increased speed of 92 m/s?
Answers
Answer:
A dump truck is being filled with sand. The sand falls straight downward from rest from a height of 2.00 m above the truck bed, and the mass of sand that hits the truck per second is 55.0 kg/s. The truck is parked on the platform of a weight scale. By how much does the scale reading exceed the weight of the truck and sand?
So as sand falls to the bed of the truck, the truck bed exerts a force upward to bring the sand to rest from the velocity the sand has as it hits the truck. This net force up is the amount of force the scale reports above the actual weight of the truck.
This impulse force then is what changes the momentum of the sand from moving to being at rest.
Since final velocity is zero after impacting truck. Moreover, since F is pointing up and we will consider that positive, the initial velocity is pointing down which must be negative, must therefore be positive and point up. So we can now drop vector signs.
To find we use conservation of mechanically energy. Assume the sand falls from rest at the height of 2.00 m. Therefore we have initially all gravitational potential energy and just before the bed of the truck it is all kinetic energy.
Momentum is mass × velocity
according to that
momentum of car = 55× 1200= 66000m/s.kg
momentum of truck = 14 × 7800 = 109200m/s.kg
here the momentum of truck is greater by 43200m/s.kg
if the car travels at rate of 92 m/s then momentum is
= 110400m/s.kg
HOPE THIS WAS HELPFUL FOR U.