Hello. I am really concerned about how i have done. Here are my answers could someone give me a mark what they believe is likely and a equivalent grade considering the paper and the qeustions?
1a) Friction between the pipe and the beads causes electrons to transfer from the pipe onto the beads, meaning they have more electrons than protons,making them negatively charged.
ii) The volume of the beads used (75cm^3)
iii) As the size of the beads increases, the charge decreases
b) The charge decreases because the pipe is shorter, and therefore there is less friction and therefore less electrons are transfered
c) Fine powders because they have a larger surface area for friction and therefore more charge builds uo
ii) Earth the pipes
iii) To make the results more accurate
2a) Nuclear fission is the proccess where a large atomic nucleus splits into to smaller atomic nuclei fragments, wheras, nuclear fusion is the proccess where two small atomic nuclei join (fuse) together to form a larger atomic nucleus
ii) Energy
b) i) Uranium -235
ii) Same number of protons
3a) Constant speed, accelerating, decelerating
b)The distance travelled by the vehicle during the time that the braking force is applied
ii) Speed
c) 5000N in the opposite direction to the car
ii) To measure the dummy's velocity( so the force extered on it could be calculated)
iii) 4m/s^2
4 a) 2V
ii) A straight line from the origin to 2,0.8 and then a curve rising up and passing through 12,2
iii) Because there is more friction
b) 108J
5 a) That it is positively charged( they asked what does this mean about matter behind the negative charged particles)
b) Because it led to the discovery of the nucleus ( they asked why did the Rutherford experiments lead to the plum pudding model not used)
ii) A-The alpha particles went straight through and didn't go near the postively charged nucleus so it was not repelled and therefore it wasn't effected
B-The nucleus is small and has a positve charge and the alpha particles go near to the nucleus causing them to repel and being deflected off
C-The nucleus is small and has a positive charge and the alpha particles hit the nucleas and are repelled and reflected of but only a small number reflected because the nucleus is small
c) To make his theories and results more reliable
6a) 98J
b) 4.8 kgm/s ( wrong asnwer but i hope to get a mark for my working out)
ii) 4800N
iii) It increases the time taken for the ball to stop which reduces the change in rate of momentum and therefore reduces the force exerted on the fielders hand
Mark,Grade,Comments?
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