Question

Please solve these questions

Answer 1

47.
g=10m/s²
w=2500j
h=5m
w=mgh
m=2500/(10×5)=50kg

48. possess potential energy.

49.
both bodies have same mass, let it be m
K.E for 1st body=1/2mv²
k.E of 2nd body=1/2m(3v)²=9×1/2mv²
So, clearly you can know the ratio.
i.e 1:9

50.
K.E=25j
As K.E is directly proportional to the square of velocity.
so, on increasing the velocity by 3 times K.E becomes 3² times of the initial.
i.e 25×9=225j

51.
1/2m1(v1)²=1/2m2(v2)²
1×v1²=4×v2²
v1²/v2²=4/1
v1/v2=2/1=k
=>v1=2k
=>v2=k
momentum:
m1v1=1×2k=2k
m2v2=4×k=4k
m1v1/m2v2=1:2
Ratio is 1:2

52.
mass(m)=1kg
k.e=12.5kgm²/s²
1/2mv²=12.5
mv²=25
V²=25, V=5m/s
momentum (p)=mv=1×5=5kgm/s

53.
K.E=P.E
1/2mv²=mgh
V=√2gh=√2×10×9.8=√196=14m/s