# How Does Dr Hewitt Break The Piece Of Wood?

## Why does bending your legs when running Enable?

Why does bending your legs when running enable you to swing your legs to and fro more rapidly.

Bending your legs shortens them, thus reducing rotational inertia.

Torque tends to twist or change the state of rotation of the object..

## How does a force differ from an impulse?

In many cases we observe changes in the velocity of an object but we don’t know how long the force was exerted. Impulse is the integral of force. It is the change in momentum. … This change in momentum is the impulse.

## How do you calculate impulse?

The impulse experienced by the object equals the change in momentum of the object. In equation form, F • t = m • Δ v. In a collision, objects experience an impulse; the impulse causes and is equal to the change in momentum.

## Why is it easier to stop a lightly loaded truck than a heavier one that has equal speed?

It is easier to stop a lightly loaded truck than a heavier one moving at the same speed because it has less KE and will therefore require less work to stop. (An answer in terms of impulse and momentum is also acceptable.)

## How can a fully dressed person at rest in the middle of a pond on perfectly frictionless ice get to shore?

Now if you’re fully dressed on a frictionless pond at rest and you want to go to shore you have to make a sacrifice. Take off your clothes and throw them in the direction you DONT want to go. So the opposite side of the shore.

## What is the difference between momentum and impulse?

Momentum is the product of mass and velocity. However, impulse represents the change of momentum of a system over a certain period of time. The calculator of momentum takes into account only the instantaneous effects of force that acts on the system.

## What are the three principal axes of rotation for the human body?

The three principal axes of rotation in the human body are the longitudinal axis, the transverse axis, and the medial axis. The three axes of rotation in the human body are at right angles to one another.

## When a rifle with a longer barrel is fired?

When a rifle with a longer barrel is fired, the force of expanding gases acts on the bullet for a longer distance. What effect does this have on the velocity of the emerging bullet? When a rifle with a long barrel is fired, more work is done as the bullet is pushed through the longer distance.

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

Which will have the greater acceleration rolling down an incline – a hoop or a solid disk? The solid hoop would have a greater acceleration.

## Why is it tiring to push against a wall?

Why is it tiring to push hard against a solid wall even though you are doing no work? It is tiring because even though their is no displacement by pushing on the solid wall, you are still exerting a force and expending energy in the process.

## Why does one get tired when pushing against a stationary wall when no work is done on the wall?

Why does one get tired when pushing against a stationary wall when no work is done on the wall? … More force is required to stretch the strong spring, so more work is done in stretching it the same distance as a weaker spring. Two people who weigh the same climb a flight of stairs.

## How does impulse differ from force quizlet?

Terms in this set (8) How does an impulse differ from force? An impulse is force times the time that force is applied. A force is a push or a pull.

## Which of the following explains why the momentum of the eight ball is conserved?

Which of the following explains why the momentum of the eight-ball is conserved? The eight-ball is an isolated system. The cue ball rebounds with the same speed it had coming in. The “glue force” cancels the collision force.

## Why is it less damaging if you fall on a mat than if you fall on a solid floor?

Why is it less damaging if you fall on a mat than if you fall on a solid floor? The time to come to a stop will be longer on the mat. This means a longer time to stop and a smaller force. … No, momentum is not conserved, for an impulse acts on the cannonball.

## What are some other examples of motions that impulse affects?

a football player colliding with another, or a car moving at a constant velocity.a car moving at a constant velocity, or an object moving in the projectile motion.a car moving at a constant velocity, or a racket hitting a ball.a football player colliding with another, or a racket hitting a ball.

## Why do you bend your legs when you run relative to rotational inertia?

b) By bending your legs when you run, you reduce the rotational inertia of your body, which allows you to rotate them back and forth more quickly; (requires a smaller torque to move your legs). How are acceleration & rotational inertia related?

## What happens the first time Dr Hewitt lifts the bowling ball near his teeth and lets go?

Why does the bowling ball behave the way it does the first time Dr. Hewitt lifts the bowling ball near his teeth and lets go? … The extra energy from the push is converted into kinetic energy, which is then converted into more potential energy at the end of the motion than the ball had when it was released.

## Can you produce a net impulse on an automobile by sitting?

Can you produce a net impulse on an automobile if you sit inside and push on the dashboard? Only external forces produce changes in momentum, so no you cannot as it is an internal force. … After the collision, car A is observed to be at rest.

## What are 2 ways to increase impulse?

Impulse is the product of force and distance moved. 3. What are the two ways to increase impulse? Increase the force or increase the time the force acts.

## When two vehicles collide momentum is conserved?

An inelastic collisions occurs when two objects collide and do not bounce away from each other. Momentum is conserved, because the total momentum of both objects before and after the collision is the same. However, kinetic energy is not conserved.

## Would it be a dangerous mistake for a bungee jumper to use steel cable rather than an elastic cord?

Why would it be dangerous mistake for a bungee jumper to use a steel cable instead of an elastic cord. the steel cord will stretch only a little, resulting in a short time of stop and a corresponding large force. … The force will be different because the time of extension is different for each of the surfaces.