mech 1: nonlinear motion and resultant force

State the resultant force, acceleration, velocity:

L = W, T = D

L is less than W

T is less than D

Lift weight thrust drag

Zero resultant force, zero acceleration, constant velocity

Resultant force facing down, Acceleration Decreasing, downward curve motion

Resultant force facing right, acceleration facing right, slows down in a level flight

If a luggage is 200 N but on a Wang scale it is shown as 180 N what is the scale doing?

If the force has decreased from its original size, the scale is technically moving upwards therefore decreasing velocity

What’s the equation for resultant force/how would you change acceleration?

F =ma

You can use three out of the four suvat equations

Newton definition and what is another type of unit you can use instead of newtons

The resultant force which will cause one kg mass to accelerate one metres/ second² in the direction of the force

N=kgms^-2

Weight definition

the gravitational force acting on the object

What are the equations for thrust/tension?

T=Fr+W

T=m(g+a)

Frictional force definition and causes

Force the opposes motion

Contact friction between two solids or fluid friction like drag due to the collisions with the molecules of the fluid

What are different factors that might affect drag?

Speed, surface area, aerodynamics, surface texture, viscosity, temperature

How do you calculate drag?

Fv²

Why can’t we predict the velocity in the future using the equations of motion?

Let’s see if the car accelerating, the velocity increases therefore drag increases however resultant force will decrease due to this. That means the acceleration will slowly decrease within time therefore not constant.

What does it mean in a question when it says fuel being used up?

This means the acceleration has increased

Terminal velocity definition

When the resultant force acting on a falling object through a fluid is zero, the velocity is constant

What does it mean when it says at a time before reaching terminal velocity?

This means before the weight is equivalent to the resultant force so it would be between initially zero and the weight

If you’re trying to calculate something, how would you calculate the angle if the angle isn’t given but the sides are

Use soh cah toa And substitute the sides