Physics term 2 Flashcards
What is the unit of mass?
KG
What is the unit of force
N
Whats the unit of power
Watts
Which of the following statements regarding momentum is true?
a) Momentum is a scalar quantity
b) Momentum is conserved in elastic collisions only
c) Momentum is the product of mass and velocity.
d) Momentum depends on the reference frame
D) Momentum is the product of mass and velocity
An object weighs 19N on a planet where the acceleration is 3.8m/s squared what is the mass of the object
5.0kg
Give one advantage and one disadvantage of wind turbines
- No harmful gas released
- Very noisy
The diagram shows a rectangular metal block with dimensions 2.5cm3,04.5* the block is resting on the ground
The block exerts a pressure of 0.23 N/cm squared on the ground the angles that exerts pressure down is 4.5 and 2.5 what is the weight of the block
2.6N
What happens to molecules of a gas when heated
They move faster and further apart
What does Boyle law state
Pressure and volume of a gas have an inverse relationship
Define the kinetic theory of matter.
Matter is made up of small particles in constant motion.
State the relationship between pressure and volume at constant temperature.
Pressure is inversely proportional to volume.
What is the SI unit of pressure?
Pascal (Pa).
What happens to gas pressure when the temperature of a fixed volume of gas increases?
Pressure increases.
Which process involves energy being released? A) Boiling B) Melting C) Freezing D) Evaporation
C
What happens to particle motion when a substance is heated?
Particle motion becomes faster.
What happens to gas molecules when cooled?
They move slower and get closer together.
The volume of metal is 30 cm³, and its mass is 192g. Calculate the density of the metal. Include the unit
Density=mass/ volume
= 192/30= 6.4g/cm³
Fig 2.1 shows a hammer hitting a nail. The mass of the hammer head is 0.15kg, and it’s speed is 8.0 m/s before contact. Calculate the change in momentum of the hammer head.
State the impulse given to the nail in the hammer and nail system.
The hammer head is in contact with the nail for 0.0015 s. Calculate the average force between the hammer and nail.
mass of hammer head is 0.15
- Change in momentum= mass×velocity
= 0.15×8.0= 1.2kg.m/s - Impulse= change in momentum= 1.3 N.s
- Force = impulse/time = 1.2/0.0015= 800N
A cyclist exerts a force 36N to move the bike forward. Calculate the work done by this force when the cyclist travels 250 m.
Work done= force×distance
W= 36×250= 9000J
Describe how hydroelectric power station generates electrical power.
A hydroelectric power station generates electrical power by using the energy of flowing or falling water to turn a turbine connected to a generator.
Calculate the efficiency of the TV given that the energy input is 100 J and the useful output is 30 J.
Efficiency=( useful output energy/input energy) * 100
30/100100
0.3100= 30
What is the formula for calculating efficiency in an energy system?
Efficiency = Output/Input × 100
What is the unit of work done in physics?
Joules
A car of mass 1000 kg is moving at a velocity of 20 m/s. Calculate its momentum.
Momentum = Mass × Velocity = 1000 kg × 20 m/s = 20,000 kg·m/s
What is the equation for calculating work done?
Work= force × distance
If a device has an efficiency of 25% and an energy input of 200 J, what is the useful energy output?
Usefulenergyoutput=0.25×200=50J
Describe how a student can measure the volume of a piece of metal using a measuring cylinder, displacement (Eureka) can, and water as shown in Fig. 2.1.
Fill the Eureka can with water until it overflows.
Place a measuring cylinder beneath the spout to catch the displaced water.
Submerge the metal piece in the Eureka can.
Measure the volume of water collected in the cylinder, which equals the volume of the metal.
Which apparatus do you need to determine density
Balance, measuring cylinder or Eureka can, ruler or caliper
Which apparatus do you need to measure volume.
For regular objects a ruler
For irregular objects, use a measuring cylinder or Eureka can to measure the volume by displacement of water.
An object travels 50 meters in 10 seconds. What is its speed?
5 m/s
A car accelerates from 10 m/s to 30 m/s in 5 seconds. Calculate the acceleration.
4 m/s²
If a force of 15 N is applied to an object with a mass of 3 kg, what is the acceleration?
5 m/s²
A ball falls with a weight of 50 N. If the gravitational field strength is 10 N/kg, what is the mass of the ball?
5 kg
An object has a mass of 10 kg and a velocity of 2 m/s. What is its momentum?
20 kg·m/s
A car with a mass of 1000 kg is moving at 20 m/s. Calculate its momentum.
20,000 kg·m/s
Calculate the impulse when a force of 25 N acts for 4 seconds.
100 Ns
An object weighing 100 N is lifted to a height of 2 meters. Calculate the work done.
200 J
A machine transfers 500 J of useful energy out of 800 J of total energy. What is its efficiency?
62.5
If an object has a kinetic energy of 100 J and a mass of 2 kg, calculate its velocity.
10 m/s
An object of mass 5 kg is at a height of 10 meters. Calculate its potential energy (g = 10 m/s²).
500 J
A 2 kg object is moving at 3 m/s. Calculate its kinetic energy.
9 J
Work done to move a box is 300 J. If the force applied is 50 N, calculate the distance moved.
6 m
A machine does 1000 J of work in 5 seconds. Calculate its power.
200 W
A vehicle with a mass of 1500 kg stops from 20 m/s in 5 seconds. Calculate the average force applied.
6000 N
If the efficiency of a machine is 40% and the energy input is 1000 J, calculate the useful energy output.
400 J
A 5 kg object accelerates at 3 m/s². Calculate the force acting on it.
15 N
A 10 kg object is acted upon by a force of 50 N. Calculate its acceleration.
5 m/s²
A car with a mass of 800 kg moving at 15 m/s is brought to rest. What is the change in momentum?
12,000 kg·m/s
Calculate the velocity of an object with a momentum of 200 kg·m/s and a mass of 4 kg.
50 m/s
A force of 20 N acts on a 2 kg object for 5 seconds. Calculate the impulse.
100 Ns
A man pushes a trolley with a force of 120 N over a distance of 3 meters. Calculate the work done.
360 J
A box is moved 4 m with a force of 25 N. Calculate the work done.
100 J
Calculate the power if 500 J of work is done in 10 seconds.
50 W
An object of mass 3 kg moving at 4 m/s hits a wall and stops. Calculate the impulse.
-12 Ns
