Answer:
the value of vA that will allow the car to coast in neutral so as to just reach the top of the 150 m high hill at B with vB = 0 is 31.3 m/s
Explanation:
given information
car's mass, m = 1200 kg
= 100 m
= 
= 150 m
= 0
according to conservative energy
the distance from point A to B, h = 150 m - 100 m = 50 m
the initial speed 
final speed
= 0
thus,
² =
² - 2 g h
0 =
² - 2 g h
² = 2 g h
= √2 g h
= √2 (9.8) (50)
= 31.3 m/s
Answer:
1/2
Explanation:
We need to make a couple of considerations but basically the problem is solved through the conservation of energy.
I attached a diagram for the two surfaces and begin to make the necessary considerations.
Rough Surface,
We know that force is equal to,



Matching the two equation we have,


Applying energy conservation,





Frictionless surface




Given the description we apply energy conservation taking into account the inertia of a sphere. Then the relation between
and
is given by


Explanation:
Given that,
Force with which a child hits a ball is 350 N
Time of contact is 0.12 s
We need to find the impulse received by the ball. The impulse delivered is given by :

So, the impulse is 42 N-m..
We know that he change in momentum is also equal to the impulse delivered.
So, impulse = 42 N-m and change in momentum =42 N-m.
They have different accelerations because of their masses. According to Newton's Second Law, an objects acceleration is inversely proportional to its mass. Therefore the object with the larger mass, in this case the gun, will have a smaller acceleration. In the same way, the less massive object, being the bullet, will have a higher acceleration.
Hope this helps :)