Forces 1
What is the force that opposes motion?
Friction
What force is involved in a spring?
Elastic force
What does gravity equal?
9.81
What do we measure force in?
Newtons
What force keeps the Earth in orbit?
Gravity
F = ma. A mass of 70kg is moving at an acceleration of 9.8m/s. What force (F) is being exerted?
686N
If a person is diving and the downward force is 600N and the upward force is 750N, which way is he travelling?
Upwards.
Force that acts upon someone in water
Friction, water resistance.
Gravity on Mars is 3.71m/s2 and the mass of the astronaut is 65kg. What is their weight? (W=mg).
241N
What are the two main types of forces?
Balanced and unbalanced.
OR
Contact and non-contact
What is an example of a contact force?
Applied, normal, friction etc.
What is an example of a non-contact force?
What is the rate of change of velocity?
Acceleration
What is the name of the force that keeps us on the ground?
Gravity
Magnetic, electrostatic and gravitational are non-contact forces. What separates the first two from the third?
They can attract and repel, gravitational only attracts
On holiday on Mars, Gravity is 1.6N/kg. I have a mass of 80Kg. I eat 10kg of Pies. What is my new weight ?
144N
F= ma - whose Second Law is this? (DOUBLE)
Isaac Newton
What are the 4 types of friction?
Static, fluid, rolling, sliding.
Four contact forces
Friction
Air resistance
Tension
Normal contact
How do we show deceleration?
Minus sign