Kinematics
The rate of change in velocity of a baseball over time
What is acceleration?
When a player runs in a curved path, what direction is the centripetal force acting on them?
What law explains that the total momentum of a system remains constant?
The Law of Conservation of Momentum
What law explains that for every action force, there is an equal and opposite reaction force.
Newtons Third Law
The energy of a baseball due to its motion is defined as what?
Kinetic Energy
A position time graph of a ball shows a straight line with a constant slope. What does the slope of that graph represent?
Velocity of the ball
When a player swings a bat in a circular motion , they feel the bat pulling outward. What is this effect called?
Centrifugal Effect
A baseball collides with a baseball bat and goes flying at 20m/s, what type of collision is this?
Elastic
When a ball and a bat collide, the bat exert a 500N force on the ball, how much force does the ball exert on the bat?
The energy of a baseball due to its position/orientation is defined as what?
Potential Energy
A runner slides into second base and slows down. How can you determine how much distance the runner covered during the slide using a velocity time graph?
By calculating the area under the graph (v * t)
When a player swings a bat in a circular motion , they feel the bat pulling outward. Explain why this happens even though the force acts inward.
The bats inertia resists the player's force.
A baseball(m = 50 grams) is thrown at a bat at rest (m = 500 grams) at a velocity of 9.5 m/s. The ball bounces back at 5.0 m/s. What is the initial momentum of the bat?
0 kgm/s
When a ball and a bat collide, the bat exerts a 500N force on the ball. Why does the bat not move but the ball goes flying?
The bat has more mass but the same force is exerted on both the ball and the bat.
A 0.15 kg baseball is thrown at 30 m/s. How much kinetic energy does it have?
67.5J
KE = 1/2mv^2
A baseball is dropped from the top of a 25 meter roof. How does it take for the ball to hit the ground?
2.26 seconds
(x = 1/2at^2 + vit)
A baseball player runs around a curve at a constant speed of 11.1 m/s. The radius of curvature of the turn is 35 m. What is the player’s centripetal acceleration?
3.52 m/s²
a= v^2/r
A baseball(m = 50 grams) is thrown at a bat at rest (m = 500 grams) at a velocity of 9.5 m/s. The ball bounces back at 5.0 m/s. What is the initial velocity of the ball?
0.475kgm/s
One of the players on a baseball team thinks that because Newton’s Third Law indicates equal and opposite forces, there is a net force of zero and the forces balance each other out when a bat hits a ball. Why are they wrong?
The forces act on different objects.
A 0.15 kg baseball is held on top of a mountain with a height of 1000m. How much potential energy does it have?
1470J
PE = mgh = 0.15 kg * 9.8m/s^2 * 1000m
Another baseball is kicked off of a building and with an initial velocity of 3.5 m/s, at 15° north of horizontal. What is the horizontal component of the initial velocity?
3.38 m/s
A baseball player is taking a tight curve while running. The radius of the curve is 15 m, and the player is moving at 20 m/s. If the player’s mass is 80 kg, how much centripetal force must the ground provide to keep them moving in the circular path?
2133.6N
a = v^2/r = 26.67m/s^2
F = ma = 2133N
A baseball(m = 50 grams) is thrown at a bat at rest (m = 500 grams) at a velocity of 9.5 m/s. The ball bounces back at 5.0 m/s. What is the final velocity of the bat?
1.45 m/s
m1v1 + m2v2 = m3v3 + m4v4
0.475kgm/s + 0 = -0.250kgm/s + 0.5kg (v4)
v4 = 1.45m/s
A 0.15 kg baseball is traveling at 25 m/s when it collides with a bat and rebounds at –15 m/s. The contact time is 0.010 s. What force does the bat exert on the ball? What force does the ball exert on the bat?
-600N, 600N
F*T = m(vf-vi)
F = m(vf-vi)/t = -600N
A baseball (0.15 kg) is dropped from the top of a 12m high fence. What is its speed right before it hits the ground?
15.34m/s
PE = mgh = 17.64J
PE = KE = 1/2mv^2
17.64J = 1/2* 0.15kg * v^2
v = 15.34m/s