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If Newton's third law is correct, why are walls not indestructible? In applying a force to a wall, if it breaks surely it is not giving an equal and opposite force.

It is best to consider this in slow motion. First we have a wall which is at equilibrium (no external forces/all forces are balanced). Someone decides that the wall is in its way and wants to break down the ...
CW
Answered by Callum W. • Physics tutor
5232 Views

A cylindrical rod of radius 7mm and Young’s Modulus 70 GPa has a weight F applied to it. The material experiences a strain of 0.2%. What force has been applied?

Young's Modulus is defined as the ratio of stress to strain. E = stress/strain. Stress is the force per unit area, F/A. By substitution, we can see that E = F/(A x strain). Rearranging gives F = E x A x stra...
CW
Answered by Callum W. • Physics tutor
2614 Views

How come nuclei become more unstable the bigger they are?

The nucleus is made up of protons and nuetrons, which means there is an electric repulsion. The nucleus is held together by somethign called the strong nuclear force. This overrides the electromagnetic repul...
TR
Answered by Thomas R. • Physics tutor
3169 Views

A cannon ball is fired at an angle 30 degrees from horizontal from a cannon with a speed 30km/h, a) calculate how high the cannonball flies, and the horizontal distance from the cannon the cannonball reaches

convert 30km/h = 8.3 m/s calculate initial vertical speed U v = 4.15m/s, calculate initial horizontal speed = 7.19m/s apply suvat equations v = u + at, s = ut + 1/2at 2 and solve for t, s final answers s hor...
JD
Answered by James D. • Physics tutor
9157 Views

Write down the equation which links speed, distance and time

speed = distance/time
SM
Answered by Sean M. • Physics tutor
4162 Views