Answer: 12Mg/h
Explanation:
Let the spring is compressed by a distance x,before the lift stops,then
Mg(h+x)= 1/2 kx^2 ............... 1
Kx - Mg = M ( 5g ) ............ 2
Make x the subject in equation 2
Kx = 5Mg + Mg
Kx = 6Mg
x = 6Mg/k ............ 3
Put equation 3 into 1
Mg ( h + x ) = 1/2 kx^2
Mgh + Mgx = 1/2kx^2
Mgh + Mg × 6Mg/k = 1/2k × ( 6Mg/k )^2
Mgh + Mg× 6Mg/k = 1/2k 36M^2g^2/ k^2
h =18Mg/k - 6Mg/h
K = 12Mg/h
Answer:

Explanation:
We know that the gravity on the surface of the moon is,
<u>Gravity at a height h above the surface of the moon will be given as:</u>
..........................(1)
where:
G = universal gravitational constant
m = mass of the moon
r = radius of moon
We have:
is the distance between the surface of the earth and the moon.
Now put the respective values in eq. (1)

is the gravity on the moon the earth-surface.
21. light changes its direction when travelling through a new medium because denser mediums have a higher angle of refraction.
Answer:
2 seconds
Explanation:
if a ball travels 1/2 meter per second, and there's 2 halfs in a whole, 1/2 meter per second x 2 halfs in a whole meter is 2 seconds to travel a meter
let the distance of pillar is "r" from one end of the slab
So here net torque must be balance with respect to pillar to be in balanced state
So here we will have

here we know that
mg = 19600 N
Mg = 400,000 N
L = 20 m
from above equation we have



so pillar is at distance 10.098 m from one end of the slab