Answer:
A baseball (m= 149g) approaches a bat horizontally at a speed of 40.2 m/s (90 mi/h) and is hit straight back at a speed of 45.6m/s (102mi/h). If the ball is in contact with the bat for a time of 1.10ms, what is the average force exerted on the ball by the bat ? Neglect the weight of the ball, since it is so much less than the force of the bat. Choose the direction of the incoming ball as the positive direction.
Explanation:
Use the impulse equation (a form of Newton's 2nd Law): FΔt = Δ(mv) where Δ means "change in"
The change in momentum is mBB(vf - vi) = (.150 kg)(-46.9 m/s - 40.5 m/s)
Divide this by the time interval and you get F exerted by the bat in Newtons.
Take care.
Answer:
3.8 secs
Explanation:
Parameters given:
Acceleration due to gravity, g = 9.8 
Initial velocity, u = 11.76 m/s
Final velocity, v = 49 m/s
Using one of Newton's equations of linear motion, we have that:

where t = time of flight of arrow
The sign is positive because the arrow is moving downward, in the same direction as gravitational force.
Therefore:

The arrow was in flight for 3.8 secs
The Huns' invasion of Europe caused a mass migration driving Germanic tribes of Northern Europe to the borders of the Roman Empire which led to the Barbarian attacks on Rome.
Answer:

Explanation:
In order to calculate the angular momentum of the particle you use the following formula:
(1)
r is the position vector respect to the point (0 , 5.0), that is:
r = 0m i + 5.0m j (2)
p is the linear momentum vector and it is given by:
(3)
the direction of p comes from the fat that the particle is moving along the i + j direction.
Then, you use the results of (2) and (3) in the equation (1) and solve for L:

The angular momentum is -30 kgm^2/s ^k