(Original post by khalidpatel)
unoffical markscheme guys:
Q1. B, has the steepest line/highest gradient
q2. Resultant force at start is zero. Then driving force increases whilst friction force stays the same. Eventually force of friction increases, reducing the resultant force.
q3. Explain why the rod is negative
the rod is negatively charged as the electrons from the woollen cloth have been transferred the rod by rubbing.
The balance reading increases because opposite charges repel
to prove this theory the student would have to do an experiment and collect data in a graph to conclude the results. The student would collect the balance reading data when the rod is at different distances away from the balance. The student should also repeat these results in order to improve reliability
q4. If the hypothesis is correct, what happens to the current?
The current is doubles
why was a line graph used, not a bar chart
it was not in a bar graph as bother variables were continuous
what is the most likely reason for the anomolous result
human error (reading the data incorrectly)
draw the line of best fit
draw line on the graph
yes that is correct the current doubles as the pd doubles eg (used data from graph as example)
d.c. = current flowing in one direction.
Charge = 36,000 coulombs
kinetic energy = 2,160j ( 0.5*120kg * 6m/s2= 2160j)
distance travelled would decrease, because the weight of the body increases therefore more force is required to move the body because :
Velocity = momentum/mass
momentum is not conserved because an external force was applied.
Conservation of momentum is when :
Total momentum before interaction = total momentum after interaction
mass of skateboard = 2.2kg (55kg*0.4=22 22/10= 2.2kg)
mass number = number of protons + number of neutrons
alpha releases two neutrons and two protons whereas beta replaces the neutron with a proton and emits an electron.
212 ........ 208 .... 4
83 bi -> 81 ti + 2 he
alpha and beta cannot produce the same element since the number of neutrons and protons they release vary. In addition, beta releases an electron. Alpha decay and beta decay of 212 bi cannot ever produce the same element as both have different mass and proton numbers