physics
What is the difference between a scalar and a vector quantity?
A scalar quantity is magnitude, whereas a vector quantity is magnitude and direction.
An arrow can represent a vector quantity, what do the aroow's length and direction represent?
The length of the arrow represents the magnitude and the direction the arrow is oointing represents which way the object is travelling.
What is a force?
A force is a push or pull that is caused by interaction.
Give 4 exapmles if contact forces.
Friction, air resistance, tension in ropes and normal contact force.
Give 3 examples of non-contact forces.
Magnetic force, gravitational force and electrostatic force.
Is force a scalar or vector quantity?
force is a vector quantity.
What is weight?
Weight is the force acting on an abject due to gravity.
What causes us to feel the force of gravity at the Earth's surface?
We can feel the force of gravity at the Earth's surface because the force is the strongest at the surface.
What two factors affect the weight experienced by an object?
Two factors that affect the weight experienced by an object are: changes in location and if the gravitational field strength is different.
What is weight measured in?
Newtons.
What is the formula for calculating the weight of an object?
Weight = Mass × Gravitational field strength
What is an object's centre of mass?
Where the force is acting from a single point on the object.
Which instrument can be used to measure weight?
A calibrated spring balance or a Newtonmeter can be used to measure weight.
What is a free-body diagram?
A diagram showing all the forces acting on an object.
What is a resultant force?
The overall force on a point or object.
How do you work out the resultant force acting on a car whose engine provides 1500N of motive force and it experiences 1100N of drag?
1500 - 1100
What does "resolving" a force mean?
Resolving a force means breaking down a single force into two or more component forces that act at right angles to each other.
What is work done?
Work done is when a force moves an object through a distance, energy is transferred and work is done on the object.
What is the equation for calculating work done?
Work done = Force × Distance
What unit is work done measured in?
Joules (J)
How many newton-metres are equivalent to 12 Joules?
12 Joules = 12 Newton-metres
Decribe the forces acting in an equilibrium.
The forces are balanced in an equilibrium.
when work is done by a car's brakes to slow a car down using friction, what happens to the temperature of the car discs?
It increases.
What is the difference between elastic and inelastic deformation?
Elastic defamation is when the object can go back to its original shape and length, whereas inelastic deformation is when an object can't do that.
What is the extension of an elastic object, such as a spring, directly proportional to?
The extension of a stretched spring is directly proportional to the load or force applied.
What is the equation that defines this relationship? (the relationship between force and extension)
Force = Sring constant × Extension
What is the limit of proportionality?
The limit of proportionality is the maximum stress that a material can withstand before it starts to deform permanently.
How do you find the force constant and work done from a linear force-extension graph?
It's the number on the Y-axis that is in line with where the line starts to curve.
What's the equation used to find the energy in an object's elastic potential energy store?
Energy = 1/2 × spring constant × extension^2
What are the two units for spring constant?
K and (N/m)
What form of energy is stored in a spring when it is stretched?
Elastic potential energy.
Define a moment.
A moment is the turning effect of a force on an object around a fixed point or axis.
What is the equation for calculating the size of a moment?
Moment = Force × perpendicular distance
If a seesaw is balanced, what can you say about the moments?
The sum of the clockwise moments is equal to the sum of the anti-clockwise moments.
How much elastic potential energy is stored in a spring extended by 0.3m with a spring constant of 1.5 N/kg? (Ep = 1/2 k e^2)
Ep = 1/2 × 1.5 N/kg × (0.3)^2
0.3^2 = 0.09
Ep = 1/2 × 1.5 N/kg × 0.09
Ep = 0.0675J
What is the equation that defines momentum?
Momentum = Mass × Velocity
State an equation for calculating the pressure at the surface of a fluid. Give the units of pressure.
Pressure = Density of the fluid × Depth of the fluid
The unit of pressure is Pascal (Pa).
Explain why the pressure increases as you go deeper into a column of a liquid.
Every layer of liquid has a weight and they press down on each other. So, the deeper you go, the more layers of water push down on each other.
What causes an object to float?
The buoyant force pushes up on the object and the weight of the object pushes back down due to gravity. if the buoyant force is greater than the weight of the object, the object will float.
Explain how and why atmospheric pressure varies with height.
Earth's gravity pulls the air molecules towards the surface, causing them to be more densely packed near the surface. As you go higher, the force of gravity on the air molecules decreases, leading to a decrease in air density and pressure.
What unit is momentum measured in?
Kilogram meter per second (kg m/s).
What is the principle of conservation of momentum?
The total momentum of a system remains constant if no external forces act on the system.