P1 Fc Before Exam

Question 1

Give an equation linking spring constant and frequency

Answer 1

F= 1/2pi x square root of(k/m)

Question 2

Give an equation for energy using Amplitude and spring constant

Answer 2

E=1/2 x K x A^2

Question 3

Explain why an astronaut feels weightless in a space vehicle

Answer 3

Because the astronaut in the space vehicle are travelling at the same speed and there is no normal reaction force between the astronaut and the space vehicles floor

Question 4

What mechanisms can we use to have an accurate experiment for determining acceleration of free fall

Answer 4

Using a trapdoor
And an electromagnet and light gates

Question 5

What is drag

Answer 5

The frictional force for an object travelling through a fluid

Question 6

Definition for centre of mass

Answer 6

A single point of an object that the whole weight is considered to act through

Question 7

Describe the velocity against time graph for terminal velocity /when an object reaches maximum velocity

Answer 7

A decreasing gradient from 0 which flattens out

Question 8

Describe the acceleration against time graph for terminal velocity

Answer 8

Acceleration at max when t=0 this decreases exponentially and reaches 0

Question 9

When will an object float in a liquid

Answer 9

When the object has a lower density than the fluid

Question 10

Definition for upthrust

Answer 10

The weight of fluid displaced by an object when it is submerged

Question 11

State archimedes principle

Answer 11

When a body is partially or fully submerged in a fluid it will experience an upthrust equal to the weight of fluid it has displaced

Question 12

State principle of moments

Answer 12

The sum of the acw moments = the sum of the cw moments

Question 13

What is a couple

Answer 13

A pair of forces of equal size which act parallel to eachother but in the opposite direction

Question 14

Def for moment and torque

Answer 14

Moment = the force times the perpendicular distance from the pivot to the line of action of the once
Torque= the size of one of the forces in a couple x the perpendicular distance between the forces

Question 15

Def for work done

Answer 15

The force causing motion x the distance moved in that direction

Question 16

How can we find the work done from a force extension graph

Answer 16

Work done = area under force-extension graph
Work done = elastic potential energy

Question 17

What is the area under a stress-strain graph

Answer 17

Gradient = young modulus
Are = elastic potential energy per unit volume

Question 18

Give equation for impulse

Answer 18

Impulse= change of momentum
Impulse= f x change in time

Question 19

What is the area under under a force time graph equal to

Answer 19

Impulse ( change in momentum)

Question 20

What is conserved in elastic and in elastic collisions

Answer 20

Elastic- KE and momentum
In elastic - momentum

Question 21

State Newton’s second law

Answer 21

The resultant force is directly proportional to the rate of change of momentum

Question 22

State newtons 1st law

Answer 22

An object will remain in equillibrium unless a resultant force acts on the object

Question 23

How is the absolute temp scale different to the Celsius scale

Answer 23

It does not depend on the property of any specific material , Celsius scale uses the boiling and freezing points of water

Question 24

Explain the structure of a gas liquid and solid

Answer 24

Gas- particles are free to move around with constant random motion no forces of attraction between particles
Liquid- particles constantly moving and free to move past eachother but are attracted to eachother
Solid- particles vibrate about fixed positions held by strong attractive forces

Question 25

Explain thermal equillibrium

Answer 25

Thermal energy is transferred from a higher temp to regions of lower temp until all regions are in equillibrium

Question 26

Def of specific heat capacity

Answer 26

The amount of energy needed to raise the temp of 1kg of substance by 1 K

Question 27

State Keplers three rules

Answer 27

The first law states that each planet move in an elliptical orbit around the Sun with the sun at one focus The second law states that a line segment joining the Sun to a planet will sweep out equal areas and equal time segments The third law states that the period of the orbit and the main distance between the Sun and the planet are related by T squared is proportional to radius cubed

Question 28

Mason is a spacecraft which orbits Mars an error stationary orbit for Mars is the equivalent of a Geo stationary orbit for us explain why maven would not be placed in an arrow stationary orbit where the average distance from the centre of Mars is 20,000 km

Answer 28

Maven needs to be within the atmosphere of Mars therefore cannot be far away. This is to be able to see the whole planet and not just the atmosphere.

Question 29

Define specific latent heat of fusion

Answer 29

The energy required per unit mass to change the state of a substance from a solid to a liquid without changing its temperature

Question 30

How do you find the ratio of speed with two moving objects?

Answer 30

Find the ratio of the distance moved by the two objects

Question 31

Give an equation for root means square speed using the molar mass of one molecule, you are not given the mass of the substance

Answer 31

1/2 M C^2=3/2 R T

Question 32

A loudspeaker is mounted on a bench and produces sound waves at a certain frequency and has a microphone receiving the sideways. Explain what type of motion this is an example of.

Answer 32

Simple harmonic motion

Question 33

State one property of a black hole

Answer 33

It is infinitely dense

Question 34

Give a definition for accuracy and precision

Answer 34

Accuracy is the closeness of a measured value to the true value Precision is the closeness of agreement between measured values which are obtained by repeated measurements

Question 35

Given equation for angular velocity linking with spring constantt

Answer 35

- w^2=k/m

Question 36

A suitcase weighing is 200 N and it is placed on a weighing scale and a lift the scale reads 180 N when the lift is moving describe the motion of the lift

Answer 36

He left is moving up with a decreasing velocity

Question 37

What is weins constant

Answer 37

2.9 x 10^-3

Question 38

What is the value for hubbles constant in s^-1vand in kms^-1Mpc^-1

Answer 38

2.3 x 10^-18 s^-1 68 kms^-1Mpc^-1

Question 39

State an event which will cause a gamma ray burst

Answer 39

The collapse of a massive star into a neutron star or black hole

Question 40

What is meant by a standard candle

Answer 40

An object with a known magnitude

Question 41

State an equation with power and temperature

Answer 41

P= stefans constant x A x T^4

Question 42

Why is the evolution of a supergiant star bad

Answer 42

The ruminants will undergo a supernova and the core will become a black hole or a neutron star which will cause a gamma ray burst

Question 43

Lead has a specific heat capacity of 130 explain what is meant by this

Answer 43

Lead requires 130 J to raise the temperature of 1 kg kilogram of lead by one kelvin without changing its state

Question 44

Give an equation for the change of mass per second when the luminosity is given

Answer 44

=L/c^2

Question 45

How do you find the route mean square speed of a set of values?

Answer 45

First square each value then find the mean of the square values and then square root them

Question 46

Explain which values of lambda you use when finding Z

Answer 46

Z= change of lambda/lambda= lambda2-lambda1/lambda1 Lambda2= the wavelength observed from earth in the galaxy Lambda 1= the wavelength observed inside earth or in a laboratory

Question 47

When the displacement varies with time, for simple harmonic motion which equation do you use if you began timing when the displacement was at its maximum or when the displacement is at the equilibrium?

Answer 47

When displacement is at the amplitude initially you use the cos equation If it started from his equilibrium position, use the sin equation

Question 48

When drawing the graph of the simple harmonic motion of displacement against time, describe the graph of a velocity against time in comparison

Answer 48

At maximum velocity, there will be minimum displacement and the velocity against time graph will be a negative and the displacement graph would be a positive cos

Question 49

Give an equation linking gravity and amplitude in simple harmonic motion

Answer 49

G=A(2pif)^2

Question 50

A graph of gravitational potential against the radius is given of a planet. How can we find the value of G at a specific point and given an equation for this?

Answer 50

If you find the gradient at that specific point, you will be given the value of G at that point in other words = g=- change of gravitational potential/change of r

Question 51

How can we find the work done using gravitational potential?

Answer 51

Work done equals mass times the change in gravitational potential

Question 52

What does the area under a force against radius graph give?

Answer 52

The work done in order to move the object from one point to another

Question 53

How can we derive the gravitational potential energy equation?

Answer 53

We know that the gravitational potential energy is the work done per unit mass so the gravitational potential energy E can be given by E=m(vg) Where? Vg=-GM/r We can then sub this into the first equation 

Question 54

How can we derive Keplers a third law?

Answer 54

For circular motion v =2pir/T And we know that we can find the orbital speed by equating the gravitational force and the central PT force equations giving us v=square root(GM/r) we can then equate these and rearrange for the equation

Question 55

How can we derive the equation for the internal energy of an ideal gas 

Answer 55

You’re gonna start off with PV=NKT and we also know that PV =1/3(N)(m)(c^2) We can equate these two and cancel out the end to give M(c^2)=3KT Then we multiply each side by a half

Question 56

On what part of earth would minimise the amount of fuel required to launch a satellite into its orbit?

Answer 56

If you launch a satellite at the equator with some speed, it will have the largest initial kinetic energy due to the earth rotation

Question 57

The magnitude of the gravitational potential at the Earth surface due to the mass is about 6.3 mega juice per kilogram, a satellite that has a mass of 1200 kg and the radius of its orbit is 4.2 mega metres is orbiting earth explain how to calculate the gain in gravitational potential energy of the satellite when it is placed into the orbit from the earth surfac

Answer 57

First find the gravitational potential at the height of the orbit therefore you’re going to use the radius of 4.2 mega metres , then you’re gonna find the change in the gravitational potential using the gravitational potential at Earth then multiply this by the mass, do the gravitational potential at earth minus the gravitational potential at its orbit this is the energy gained