Answer:
the moment of inertia with the arms extended is Io and when the arms are lowered the moment
I₀/I > 1 ⇒ w > w₀
Explanation:
The angular momentum is conserved if the external torques in the system are zero, this is achieved because the friction with the ice is very small,
L₀ = L_f
I₀ w₀ = I w
w = w₀
where we see that the angular velocity changes according to the relation of the angular moments, if we approximate the body as a cylinder with two point charges, weight of the arms
I₀ = I_cylinder + 2 m r²
where r is the distance from the center of mass of the arms to the axis of rotation, the moment of inertia of the cylinder does not change, therefore changing the distance of the arms changes the moment of inertia.
If we say that the moment of inertia with the arms extended is Io and when the arms are lowered the moment will be
I <I₀
I₀/I > 1 ⇒ w > w₀
therefore the angular velocity (rotations) must increase
in this way the skater can adjust his spin speed to the musician.
Answer:
0.014s
Explanation:
Given parameters:
mass of golf ball = 0.059kg
force applied = 290N
velocity = 69m/s
initial velocity = 0m/s
Unknown:
Time of contact = ?
Solution;
We know that momentum is the quantity of motion of body possess;
Momentum = mass x velocity
Momentum = 0.059 x 69 = 4.1kgm/s
Also; impulse is the effect of the force acting on a body;
impulse = force x time = momentum
So;
Force x time = momentum
Time = =
= 0.014s
Answer:
2.72 cycles
Explanation:
First of all, let's find the time that the stone takes to reaches the ground. The stone moves by uniform accelerated motion with constant acceleration g=9.8 m/s^2, and it covers a distance of S=44.1 m, so the time taken is
The period of the pendulum instead is given by:
Therefore, the number of oscillations that the pendulum goes through before the stone hits the ground is given by the time the stone takes to hit the ground divided by the period of the pendulum:
Answer:
The force exerted by the ball on the bat has a magnitude of 100 N and its direction is exactly opposite to that of the force exerted by the bat on the ball.
Explanation:
Recall that Newton's third law tells us that : "For every action, there is an equal and opposite reaction."
Therefore if the bat acts on the ball with a force of 100 N, the ball acts on the bat with a similar magnitude of force (100 N) but direction opposite to the original force.