Efficiency = (energy that does the job) / (total energy used)
= (45 J) / (120J)
I think you can handle the division.
C. meter per second
Velocity and speed share the same SI unit.
Fluorine (F) has higher potential energy as Neon (N) is a noble/inert gas.
Fluorine will lose another electron to gain stability.
Just ignore the horizontal component
if you have a vertical displacement of 15m, 0ms^1 initial velocity, end velocity is ignored, we know the acceleration due to gravity as 9.81ms^2 so we can work out the time using SUVAT
S=15
U=0
V=?
A=9.81
T=?
S=UT + 0.5 AT^2
UT=0
therefore,
S=0.5AT^2
rearrange to:
T=SQR (2S/A)
T = 1.75 seconds
