Topic A.

How do you calculate absolute uncertainty?

It is the uncertainty given with a measurement, often written as ± a value.

How do you calculate percentage uncertainty?

(Absolute Uncertainty / Measured Value) × 100%

How do you combine uncertainties for addition and subtraction?

Add the absolute uncertainties:
ΔR = ΔA + ΔB

How do you combine uncertainties for multiplication and division?

Add the percentage uncertainties:
(ΔR / R) = (ΔA / A) + (ΔB / B)

How do you find uncertainty when raising a value to a power?

Multiply the percentage uncertainty by the power:
(ΔR / R) = n × (ΔA / A)

How do you find uncertainty when taking a root?

Divide the percentage uncertainty by the root:
(ΔR / R) = (1 / n) × (ΔA / A)

What is the formula for average velocity?

v_avg = Δx / Δt

What is the formula for instantaneous velocity?

v = dx / dt (derivative of displacement with respect to time)

How do you determine velocity from a displacement-time graph?

Velocity is the gradient (slope) of the graph.

How do you determine acceleration from a velocity-time graph?

Acceleration is the gradient (slope) of the graph.

How do you determine displacement from a velocity-time graph?

Displacement is the area under the graph.

What are the four fundamental forces?

Gravity, Electromagnetic Force, Strong Nuclear Force, Weak Nuclear Force.

What are some examples of contact forces?

Friction, Tension, Normal Force, Air Resistance, Applied Force.

What is Archimedes' Principle?

A body submerged in a fluid experiences an upward buoyant force equal to the weight of the displaced fluid.

What is buoyancy?

The upward force exerted by a fluid on a submerged or floating object.

What is the formula for apparent weight when an elevator is going down?

F apparent = m(g - a)

What is the formula for apparent weight when an elevator is going up?

F apparent = m(g + a)

What is Hooke’s Law?

F = kx (Force is proportional to the extension of a spring, where k is the spring constant and x is the extension.)

What is power?

The rate of doing work or transferring energy:
Power = Work / Time

What is specific heat capacity?

The amount of heat energy required to raise the temperature of 1 kg of a substance by 1°C:
Q = mcΔT

What is linear momentum?

Linear momentum (p) is the product of a body's mass (m) and velocity (v).

What is the equation for linear momentum?

p = mv

What are the units of momentum?

kg·m/s (kilogram metres per second)

Is momentum a scalar or vector quantity?

Momentum is a vector quantity; its direction is the same as velocity.

When is momentum conserved?

Momentum is conserved in an isolated system where no external forces act.

How does Newton's third law relate to momentum?

In a system of interacting objects (e.g., two skaters pushing each other), they exert equal and opposite forces, leading to equal and opposite changes in momentum.

What is the difference between internal and external forces in a system?

Internal forces act within the system (e.g., skaters pushing each other), while external forces come from outside (e.g., gravity, friction).

How does Newton’s second law relate to momentum?

F = Δp / Δt, meaning force is the rate of change of momentum.

What is impulse?

Impulse (J) is the change in momentum caused by a force applied over time.

What is the equation for impulse?

J = FΔt

What are the units of impulse?

kg·m/s (same as momentum)

How can impulse be determined from a force-time graph?

The area under the force-time graph represents impulse.

How does increasing the time of contact affect force?

A longer time reduces the force required for the same momentum change (e.g., seatbelts stretch to reduce force in a crash).

Why does an egg break when dropped on concrete but not on a cushion?

The cushion increases the stopping time, reducing the force acting on the egg.

Does the momentum of a ball change when it bounces off a wall?

Yes, because velocity reverses direction, changing momentum.

Is momentum conserved when a ball hits a wall?

If the system includes both the ball and the wall, momentum is conserved, but the wall's motion is negligible due to its large mass.

When does mass change affect momentum?

When an object loses or gains mass (e.g., a rocket burning fuel, a conveyor belt loading bags).

What is the momentum equation for a system with changing mass?

F = d(mv) / dt

What does the slope of a displacement-time graph represent?

Velocity.

What does the area under a velocity-time graph represent?

Displacement.

What does the slope of a velocity-time graph represent?

Acceleration.

What does the area under an acceleration-time graph represent?

Change in velocity.

What is the shape of the trajectory of a projectile?

A parabola.

In projectile motion, what is the graph of horizontal displacement vs. time?

linear with slope as velocity

What does the slope of a force vs. acceleration graph represent?

Mass ().

How does the graph of frictional force vs. applied force behave?

Linear until the limiting friction, then constant.