P1 Extended Responses To Memerse Flashcards
A ball is attached to a string and is rotated horizontally so that it has circular motion use newtons three laws to describe the balls motion
Newton’s first law
The board has a constant speed however its velocity is not constant as its direction is changing constantly therefore the ball is accelerating as the velocity changes constantly and this velocity is perpendicular to the force action towards the centre of the circle
Newton second law
The force on the ball causes the ball to accelerate in the direction of the force. This is the centripetal force which acts towards the centre of the circle.
Newton’s third law
The ball will tug on the string/the central support point with a force that is equal and opposite to the force pulling on the ball from the centre
A car is travelling on a level road. The same car is now travelling up a slope explain the effect on the distance required to bring the vehicle to rest due to the upward slope.
There is a greater downward weight component therefore there is a greater downward resultant force so there is a smaller resultant force up the slope. Therefore a smaller distance is required to do the same work to bring the vehicle to stop
A sand bag is placed on top of the seat of 12 kg on a fairground ride which rotates with a circular path and a radius about 10 m determine the effect on the horizontal displacement travelled by the object if it was a shoe from a rider rather than a bag
Tissue is lower in mass however there is no change in angular velocity or the radius as these are independent of mass therefore there would be no change in horizontal displacement
A student carries out two experiments one time for a vertical drop method and a rolling ball a method to determine values for G. The drop height is 1.2 m and the time taken to reach the ground is 0.5 seconds the length of the ramp is 1.9 m and the time taken is 0.9 seconds the angle of the ramp is changed For the experiment compare and discuss the uncertainties of the two values of that are obtained using the single measurements and describe how the student can analyse both sets of data when a full range results has been taken
As there are no repeats, both experiments will already have uncertainty and will not be accurate
The meter ruler will have an absolute uncertainty of plus or -1 mm Andy stop clock used in the experiment will have a resolution of 0.1 seconds however reaction time will have a greater uncertainty and effect the results
To calculate G we will use time squared therefore the uncertainty with double for time and the angle measured is likely to be plus or -1° and the ramp also use a sign of the angle as we need the vertical displacement therefore it is difficult to quantify uncertainty
The greatest time and a greater distance therefore it will have a reduced uncertainty however it still has the added uncertainty from the protractor and there are friction factors affect the results of the ramp
To analyse the data we can plot graph of S against T squared where the gradient will be G divided by two for both graphs and we can plot air bars and do a line of worst fit and best fit to find the uncertainty from the graph
How can we derive? Density= pressure x M/ RT
Where M= mass of one mole of gas
Start with pV=nRT
We know that density= m/V and m=nM
Therefore, we can rearrange to give n=density X V/ M
Then substitute this into our starting equation and rearrange for density equals
An airship is floating above the ground and is stationary. Explain why the weight of the air displaced by the airship has the same magnitude as the weight of the airship and its contents.
This is because the airship is stationary therefore the airship is an equilibrium to upthrust must equal the weight of the air shift
Upthrust equals the weight of the fluid displaced
An airship has a cabin suspended underneath a gas bag inflated with helium. The pressure of the helium in the gas bag is maintained at a value only slightly greater than atmospheric pressure suggest why a larger pressure is not used.
Greater pressure would increase the density of the helium therefore more collisions of helium atoms with the walls therefore this leads to more leakage of helium
A glider is placed in between two springs and is displaced so that it oscillate in simple harmonic motion when the initial displacement is increased. One of the springs increases extension while the extension of the other spring decreases explain why the maximum kinetic energy of the motion still increases.
The elastic potential energy gained from stretching the spring is greater than the elastic potential energy lost in the spring due to compression therefore the overall energy increases therefore kinetic energy also increases as elastic potential energy is transferred to the kinetic energy. Thought of the spring. Maximum velocity happens when displacement is zero so at equilibrium position and maximum velocity increases as the initial displacement increases therefore kinetic energy also increases.
Describe the formation of a neutron star and state one characteristic of it
A neutron star or originates from the remnant of a red super giant, when the star can no longer generate energy by fusion and the gravitational force exceeds the outwards radiation pressure the star then undergoes a supernova and if the core has a mass above 1.44 solar masses and below the limit of a black hole, three solar masses, the protons combined with the electrons to produce neutrons
One characteristic is that the neutron star is extremely dense
Describe an experiment for finding the terminal velocity of solid spheres falling through a fluid
Use a long clear tube containing the fluid and check the tube is vertical using a plum line
Measures the distance with a meter ruler and measure the time with a stop clock and use a video method
Use a release mechanism to drop the sphere into the fluid and use the video to determine when the ball reaches terminal velocity. You can do this by finding the velocity every 10 cm using bands and the velocity should be the same for every 10 cm travelled then repeat the experiment 3 times and find a mean and repeat the experiment using a different fluid or a different metal sphere with different our values and plot the required graph
A wooden cylinder is fully submerged in water describe and explain how the results are forced on the wooden cylinder varies from the moment the cylinder is fully submerged until it reaches its deepest point
The result of force decreases as the cylinder travels down however upthrust is constant and at the deepest point there is an upward resultant force
A bun is spun in a horizontal circle and the time period is recorded and the length of the rope is recorded. What can be done to allow accurate measurements of the time and the length and the overall experiment
Swing the bank in small angles so that the angle is less than 10°
Start timing at the centre of oscillation and stopped timing at the same point
Measure the length of the string from a fixed point to the centre of the tube the string is in
There is a lot of helium in the universe this was also true of the Earth when it was formed billions of years ago however only small cases of helium are now found in the atmosphere of earth use the kinetic theory of gases to explain why only small amount of helium are found in the atmosphere, the average velocity is 1.3 km/s and the velocity of earth is 11 km/s
A certain temperature all atoms have the same average kinetic energy and helium behaves as an ideal gas. Theaverage velocity of helium atoms are less than the escape velocity of Earth, however as helium behaves as an ideal gas D at have a range of velocities that due to the boatman distribution and some of the atoms have a greater average velocity than these escape velocity of the Earth
The universe evolved from the Big Bang describe the evolution of the universe up to the formation of the first nuclei
At the Big Bang, the universe was a singularity and then there was a period of inflation where the universe expanded rapidly, as the universe expanded it cooled down and quarks and leptons were formed then quarks combined together to form hadrons then hadrons combined together to make a nuclei
The value G is calculated from an experiment where a horizontal trolley with a card of specific length swipes under a light gate as a mass is released over a table over a pulley therefore accelerating the trolley horizontally, it is suspected that the card on the trolley did not pass at right angle through the light beam discuss the effect this may have on the value of G
The card appears for a shorter time as it is not at right angles to the light gate therefore the speed calculated is larger than the actual velocity therefore if we were to draw a graph of displacement against T squared the gradient would be steeper therefore the G calculated is greater
