You didn't Provide choices to choose from. Please fix question and I'd love to be able to help.
Answer:
C
Explanation:
Its because electron does its thing with energy to
its orbital
Answer: 6250 joules
Explanation:
The work needed to lift an object of mass M by a height H is equal to:
w = M*g*H
where h = 10m/s^2
then the total work that he did is equal to the sum of the work for every stone:
W = (100kg*g*H) + (120kg*g*H) + (140kg*g*H) + (160kg*g*H) + (180kg*g*H)
= (100kg + 120kg + 140kg + 160kg + 180kg)*g*H
= (500kg)*g*H
and now we can repalce g by 10m/s^2 and H by 125cm
But you can notice that we have two different units of distance, so knowing that 100cm = 1m
we can write H = 125cm = (125/100) m = 1.25 m
Then we have:
H = 500kg*10m/s^2*1.25m = 6250 J
if you multiply the mass of an object by the acceleration due to gravity, you will obtain the object's weight. mass is an intrinsic property of matter
looks like a good answer ...
Answer:

Explanation:
given,
coefficient of kinetic friction, μ = 0.25
Speed of sled at point A = 8.6 m/s
Speed of sled at point B = 5.4 m/s
time taken to travel from point A to B.
we know,
J = F Δ t
J is the impulse
where F is the frictional force.
t is the time.
we also know that impulse is equal to change in momentum.

frictional force
F = μ N
where as N is the normal force
now,






time taken to move from A to B is equal to 1.31 s