# AP physics

posted by .

On Block has a mass M=500 g, the other has mass m=460 g, they are hooked to a string and is on a pulley will one mass on either side, the pulley, which is mounted in horizontal frictionless bearings, has a radius of 5 cm. When released from rest, the heavier block falls 81.5 cam in 2.51 s (withouth the cord slipping on the pulley).

What is the magnitude of the blocks acceleration?

What is the tension in the part of the cord that supports the heavier block?

What is the tension in the part of the cord that supports the lighter block?

What is the magnitude of the pulleys angular acceleration in rad/s squared?

What is its rotational inertia?

• AP physics -

You have distance, time, intial velocity, compute acceleration.

d=1/2 at^2

2j) Tension= mg-acceleration*m

3) Tension= mg+ma
in the case of each of those, m is the mass of the block being investigated.

one knows tangential acceleration, a. angular acceleartion= tangential acceleartion /radius

Finally, w= I*alpha, solve for I.

• AP physics -

Both blocks accelerate at the same rate; the lighter one goes up and one the more massive one down. The distance fallen Y in time t obeys the rule
Y = (1/2) a t^2. Therefore a = 2Y/t^2 = 25.9 cm/s^2. (If the pulley had no mass, it would accelerate somewhat faster-- at a rate (M1-M2)g/(M1+M2)= 28.3 cm/s^2, but they don't ask for that). M2 is the mass of the heavier block: 0.5 kg. M1 = 0.46 kg

For the cord tension T2 on the heavier block, solve
M2 g -T2 = M2 a
T2 = M2 (g-a) , where g = 980 cm/s^2 = 9.8 m/s^2. I get 47.7 N

For the tension on M1, solve
M1 g -T1 = -M1 a, since it accelerates upward, in the opposite direction from the gravity force. In this case, T1 = M1 (g+a)

The pulley's angular acceleration is:
alpha = a/R, where R is the pulley's radius.

The rotational moment of inertia (I) of the pulley is given by
Torque = (T1 - T2)*R = I*alpha.
Use the alpha value from the previous step.

• AP physics -

I get 4.77 N for T2..do i have a decimal wrong?

• AP physics -

Yeah, I got 4.8N. You forgot to convert acceleration (28.3 cm/s^2) into m/s^2. So, (0.5kg)(9.8m/s^2-0.283m/s^2) = T2

## Similar Questions

1. ### Physics

A massless string runs around two massless, frictionless pulleys, where one pulley is attached to the ceiling, and the other is suspended with a mass m. An object with mass m = 17 kg hangs from one pulley. A force F is exerted on the …
2. ### physics

A 15.0 kg mass and a 10.0 kg mass are suspended by a pulley that has a radius of 10.0 cm and a mass of 3.0 kg. The cord has negligible mass and causes the pulley to rotate without slipping. The puller is frictionless and may be treated …
3. ### physics

The system shown below consists of a block of mass M = 4.4 kg resting on a frictionless horizontal ledge. This block is attached to a string that passes over a pulley, and the other end of the string is attached to a hanging block …
4. ### physics

The system shown in the figure below consists of a m1 = 5.52-kg block resting on a frictionless horizontal ledge. This block is attached to a string that passes over a pulley, and the other end of the string is attached to a hanging …
5. ### physics

The system shown in the figure below consists of a m1 = 5.52-kg block resting on a frictionless horizontal ledge. This block is attached to a string that passes over a pulley, and the other end of the string is attached to a hanging …
6. ### physics

The system shown in the figure below consists of a mass M = 3.5-kg block resting on a frictionless horizontal ledge. This block is attached to a string that passes over a pulley, and the other end of the string is attached to a hanging …
7. ### Physics Help Needed

Two blocks are connected by massless string that is wrapped around a pulley. Block 1 has a mass m1=6.90 kg, block 2 has a mass m2=2.30 kg, while the pulley has a mass of 1.70 kg and a radius of 12.2 cm. The pulley is frictionless, …
8. ### Physics

Block A (Mass = 3.500 kg) and Block B (Mass = 2.450 kg) are attached by a massless string Block A sits on a horizontal tabletop. There is friction between the surface and Block A. The string passes overa frictionless, massless pulley. …
9. ### physics

Acceleration of a Mass in a Pulley System Block 1 of mass m1 slides on a frictionless plane inclined at angle θ with respect to the horizontal. One end of a massless inextensible string is attached to block 1. The string is wound …
10. ### Physics

There is a block of mass 1 on a frictionless surface attached to a string. The string goes over a frictionless pulley. The pulley is a hoop with a rotational inertia of I=MR^2. The other end of the string is attached to a hanging block …

More Similar Questions