A 10kg roller coaster does a loop-de-loop and it’s your job to make sure it is safe. The people will fall out if the cart’s speed is less than 40m/s when it goes upside down. How high up does the car have to be at point A to make it? Fill in everything else as well. Location

PE

KE

TE

A

h =

v = 0m/s

B

h = 0m

v =

C

h = 15m

PE=m*g*h

v = 40m/s

KE=0.5*m*v2=

TE=PE+KE

D

h = 0m

v =

E

h = 10m

v =

F

h = 20m

v =

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current

Ithink it’s: light bounce if off a mirror