Contents

- 1 How does Dr Hewitt break the piece of wood?
- 2 Why does the rotational inertia of the rod with the attached mass closer to your hand?
- 3 How does the rotational inertia of the rod with the mass toward the bottom compare with the rotational inertia of the mass toward the top?
- 4 How does the minimum force needed to hoist a load change as you increase the number of pulleys from one to two then three then four?
- 5 Which case requires greatest impulse?
- 6 When two vehicles collide momentum is conserved?
- 7 Is angular momentum always conserved?
- 8 Are we most stable when your weight is directly over your base?
- 9 What does rotational inertia depend on?
- 10 Which will have the greater acceleration rolling down an incline?
- 11 How do you find mass with speed and inertia?
- 12 Can a force produce a torque when there is no lever arm?
- 13 What are the 3 types of pulleys?
- 14 Does a single pulley reduce force?
- 15 How do screws make work easier?

## How does Dr Hewitt break the piece of wood?

How does Dr. Hewitt break the piece of wood? He causes a change in momentum of his hand over a short period of time.

## Why does the rotational inertia of the rod with the attached mass closer to your hand?

Why does the rotational inertia of the rod with the attached mass closer to your hand compare the way it does with the rotational inertial of the rod with the attached mass farther away? Rotational inertia depends on whether the mass is farther or closer to the point of rotation.

## How does the rotational inertia of the rod with the mass toward the bottom compare with the rotational inertia of the mass toward the top?

How does the rotational inertia of the rod with the mass toward the bottom compare with the rotational inertia of the mass toward the top? The rotational inertia of the rod with the mass closer to the top is equal to the rotational inertia of the rod with the mass closer to the bottom.

## How does the minimum force needed to hoist a load change as you increase the number of pulleys from one to two then three then four?

How does the minimum force needed to hoist a load change as you increase the number of pulleys from one to two, then three, then four? The minimum force needed to hoist the load becomes half, then one-third, then one-fourth.

## Which case requires greatest impulse?

The impulse required is greatest when the ball is caught and then thrown back because the impulse required equals the change in momentum.

## When two vehicles collide momentum is conserved?

In a collision between two objects of identical mass, the acceleration values could be different. Total momentum is always conserved between any two objects involved in a collision. When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater collision force.

## Is angular momentum always conserved?

In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum. It is an important quantity in physics because it is a conserved quantity —the total angular momentum of a closed system remains constant.

## Are we most stable when your weight is directly over your base?

As long as your center of gravity is more or less above your feet, your body will always be balanced and you won’t tip over.

## What does rotational inertia depend on?

• The rotational inertia (I) depends on the mass of the. object, its shape, and on how. the mass is distributed.

## Which will have the greater acceleration rolling down an incline?

A bowling ball will have a greater acceleration because it has more mass concentrated toward its center, while much of a volleyball’s mass is concentrated toward its eage (it’s hollow). Thus, a volleyball has more rotational energy relative to its weight and takes longer to roll down a hill.

## How do you find mass with speed and inertia?

Rotational Inertia = m(r)(r), where “m” is the mass and “r” is the radius or the distance between the object and the axis. Calculate the rotational inertia for a solid cylinder or disk of radius “r” and mass “m” by the formula, inertia =1/2(m)(r)(r).

## Can a force produce a torque when there is no lever arm?

An applied force can result in zero torque if there is no lever arm or the applied force is parallel to the lever arm (see Figure 3 and 4 below). Direction of force: these applied forces result in no torque on the wrench because the applied force is parallel to the lever arm.

## What are the 3 types of pulleys?

These are different types of pulley systems:

- Fixed: A fixed pulley has an axle mounted in bearings attached to a supporting structure.
- Movable: A movable pulley has an axle in a movable block.
- Compound: A combination of fixed and movable pulleys forms a block and tackle.

## Does a single pulley reduce force?

One wheel. If you have a single wheel and a rope, a pulley helps you reverse the direction of your lifting force. So, as in the picture below, you pull the rope down to lift the weight up. It doesn’t alter the force in any other way.

## How do screws make work easier?

Screws move objects to a greater depth (or higher elevation) by increasing the force applied to the screw. The mechanical advantage of a screw is always greater than 1 because the output force applied by the screw is greater than the input force applied to the screw.