P9 and P10 - Force and Motion Flashcards
What is the equation for speed?
speed = distance travelled / time taken
v (m/s) = d (m) / t (s)
What is the gradient of a distance - time graph?
speed
What is acceleration?
Change in velocity
How do you calculate acceleration?
acceleration = change in velocity / time taken
acceleration = final velocity - starting velocity / time taken
a (m/s^2) = v (m/s) - u (m/s) / t (s)
what is the unit for velocity?
metres per second, m/s
what is the unit for acceleration?
metres per second squared, m/s^2
what is a negative acceleration also called?
Deceleration
What is the equation for force?
Force = mass x acceleration
F = m x a
F (Newtons) = m (kg) x a (m/s^2)
What happens to a mass if a resultant force acts on it?
It will accelerate.
What is mass?
The amount of matter an object has in kilograms, kg
What is weight?
The force acting on a mass due to gravity.
What is the equation for weight?
Weight = mass x gravitational field strength
W = m x g
W (N) = m (kg) x g (N/kg)
If I went to another planet would my weight be different?
Yes, weight is a force due to the gravity of the planet acting on a mass.
If I went to another planet would my mass be different?
No, mass is the amount of stuff that makes you up and would be the same.
What is g, the gravitational field strength on Earth?
g= 9.81 m/s^2
When stopping a car what affects the total stopping distance?
Thinking distance and braking distance
Stopping distance = thinking distance + braking distance
What is thinking distance?
the distance travelled by the car in the time it takes the driver to react.
What is braking distance?
The distance travelled by the car whilst the brakes are applying a stopping force.
What factors affect thinking distance?
Distractions such as phones.
How alert the driver is being tired will slow reactions.
If the driver is under the influence of drugs or alcohol their reactions may be slower.
What factors affect braking distance?
The condition and maintenance of the car.
The road conditions.
Wet or icy roads.
What is Hooke’s law?
The extension of a spring is proportional to the force applied to it within its limit of proportionality.
What is the equation for extension of a spring?
Force = spring constant x extension
F = k x e
F (Newtons) = k (N/m) x e (m)
What can you use to measure the extension of a spring?
a ruler
