Newton's laws
What is Newton's 1st law?
An object in motion will remain motion and an object at rest will remain at rest, unless acted upon an external net force
What is Kinetic friction?
Friction that resists motion and goes in the opposite direction of motion
What is tension?
A pulling force from a taut rope
An object accelerates 5 m/s2 to the right when a force of 10 newtons is applied to it.
What is the mass of this object?
2 kg
What is Newton's 2nd law?
F = ma
What is static friction?
Friction that prevents sliding
Why are bridge cables braided?
They reinforce cables and divide load between each cable.
A 7 kg block of wood is almost about to slide across a wooden floor. The coefficient of static friction is 0.691.
What is the force of static friction?
47.4 N
What is Newton's 3rd law?
For every action there is an equal and opposite reaction
What does the coefficient of friction represent?
What are its units?
How much friction is present between an object and surface.
It is unitless
How is tension calculated?
By using Newton's 2nd law
A 15 kg block is laying on a 30o ramp.
What is the magnitude of the normal force?
127 N
Newton's 3rd
What is the formula for friction?
Friction = coefficient x Normal
A bridge requires 10,000 N of force to be supported and is supported by 1,000 cables.
How many Newtons is each cable supporting?
10 N
A 100 kg trailer is pulled by a cable and is accelerating horizontally at a rate of 3 m/s2.
The cable is pulling the trailer at an angle of 30o, what is the force of tension on the cable?
346 N
Which one of Newton's laws is responsible for satellites orbiting the Earth without propulsion?
Newton's 1st
What is the normal force?
A contact force that is perpendicular to the surface.
A dog sled with a mass of 100 kg is accelerating to the right at a rate of 3 m/s2.
What is the force of tension pulling the rope?
300 N
A 200 kg elevator is accelerating upwards at a rate of 1 m/s2.
What is the force of tension pulling the elevator?
2160 N