1. Two books of mass (1 kg each) are kept at a distance of 1m apart and when the

Question

1. Two books of mass (1 kg each) are kept at a distance of 1m apart and when they are dropped from a heaight of 10m, it is noticed that they hit the ground at the same time although there is a gravitatoinal force of attraction between them. Justify this statement by performing appropriate calculation.

2. A plane is flying at an altitutde of 33,000 ft (1ft=30 cm) and the temperature outside is pretty cold (~-60F). Suppose, the engine fails and the plane crashes to the ground. Argue it is still a free-fall by performing appropriate calculation.

3. Assume a car of mass 1942 lbs traveling at a speed of 60 mph collides with a stalled small truck of 1942 kg. Figure out the speed of the car after collision if the truck moves forward at a speed of 40 mph. How much momentum is transferred in the process?

Can someone please help!!!

I know for number 1, I use the center of mass formula, but the height of 10 ft is throwing me off. :/

Explanation / Answer

a)The vertical acceleration of both is g and the force due to gravity between them is always horizontal. Therefore, the time taken to travel equal distances vertically, each starting from rest is the same.

b)The plane does have a horizontal velocity at that point but without the lift of the engine, it's vertical acceleration becomes equal to g. This means a free fall.

c)Conserving momentum.

1942*60=1942*2.2046*40+1942*v

v=-28.2 mph meaning it is moving in the opposite direction to the initial one.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.