Forces and Motion
The term for the force that acts towards the center in circular motion
centripetal force
The power output of a machine that does 3000 J of work in 10 seconds
300 W
The part of the electromagnetic spectrum with the shortest wavelength
gamma
The unit for electrical resistance
ohm
What is the principle of conservation of energy?
The law states energy cannot be created or destroyed, only transferred
A 500 kg car accelerates from 5 m/s to 20 m/s in 4 seconds. Calculate the force applied
1875 N
The work done when a 50 kg object is lifted 3 meters against gravity in 10s. Calculate the power.
147 J
The principle that explains why waves spread out after passing through a small gap
Diffraction
The formula relating charge, current, and time.
I = Q/t
What is the meaning of absolute zero?
the temperature at which particles have minimum to zero kinetic energy, T = -273.15K
The moment of a force is defined as this mathematical expression.
Moment = Force x Perpendicular Distance
Explain why work done is a scalar quantity even though force and displacement are vectors
Work is the dot product of force and displacement, making it scalar
The refractive index of a medium is given by this equation
n = c/v
A 60 W lightbulb operates at 240 V. Calculate its resistance.
960
Explain why gases exert pressure on the walls of their container
due to collisions of gas molecules with the walls, exerting a force per unit area aka pressure on the walls
What is it called when the net force and net moment on an object are both zero.
Equilibrium, no turning effect
What is the term for the energy loss mechanism that reduces efficiency in most mechanical systems.
friction and heat dissipation
Describe total internal reflection and state the condition for it to occur
light travels from a denser to a less dense medium at an angle greater than the critical angle
The force experienced by a 2 C charge in an electric field of 50 N/C
100 N
A radioactive substance has a half-life of 5 minutes. How much of a 200 g sample remains after 15 minutes?
25 g
Derive the equation for acceleration in terms of force and momentum
a=F/m=Δp/mΔt
A 1000 kg car is moving at 30 m/s when the driver suddenly applies the brakes, bringing the car to a complete stop over a 50 m distance. Assuming constant deceleration, calculate:
1. The work done by the braking force.
2. The magnitude of the braking force applied.
1. (-)450 kJ
2. 9 kN
The part of the electromagnetic spectrum used for medical imaging
X ray
What is the direction of the movement of wire? refer image
upwards
The definition of specific heat capacity.
the amount of energy required to raise the temperature of 1 kg of a substance by 1°C