A. Allow movement.
Muscles connect to your skeleton and they contract and move the skeleton along. <span>They help the process of movement happen in a smoother manner.</span>
Answer:
VR = 
Explanation:
A machine is a device that can be used to overcome a load by the application of an effort through a pivot. Examples are: pulleys, wedge, screw jack, wheel and axle etc.
The wheel and axle is a simple device that can be used to lift a load through a height. Its velocity ratio (VR) can be determined by:
VR = 
Note that for a practical wheel and axle, the radius of the wheel is greater than the radius of the axle.
Answer:
W = 55.12 J
Explanation:
Given,
Natural length = 6 in
Force = 4 lb, stretched length = 8.4 in
We know,
F = k x
k is spring constant
4 = k (8.4-6)
k = 1.67 lb/in
Work done to stretch the spring to 10.1 in.

![W = \dfrac{k}{2}[x^2]_6^{10.1}](https://tex.z-dn.net/?f=W%20%3D%20%5Cdfrac%7Bk%7D%7B2%7D%5Bx%5E2%5D_6%5E%7B10.1%7D)

W = 55.12 J
Work done in stretching spring from 6 in to 10.1 in is equal to 55.12 J.
Answer:
The new radius of the trajectory of the particle is four times the previous radius
Explanation:
In order to know what is the radius of the trajectory of the charged particle, if its speed is four times as fast, you take into account the following formula, which describes the radius of a charged particle in a magnetic field:
(1)
If the speed of the particle is for time as fast, that is, v' = 4v, you obtain, in the equation (1):

The new radius of the trajectory of the particle is four times the previous radius
The momentum, p, of any object having mass m and the velocity v is

Let
and
be the masses of the large truck and the car respectively, and
and V_S be the velocities of the large truck and the car respectively.
So, by using equation (i),
the momentum of the large truck 
and the momentum of the small car
.
If the large truck has the same momentum as a small car, then the condition is

The equation (ii) can be rearranged as

So, the first scenario:


So, to have the same momentum, the ratio of mass of truck to the mass of the car must be equal to the ratio of velocity of the car to the velocity of the truck.
The other scenario:


So, to have the same momentum, the ratio of mass of truck to the velocity of the car must be equal to the ratio of mass of the car to the velocity of the truck.