Question

Plz solve it with working​

Answer 1

Explanation:

m=80g=80/1000kg=0.08kg

u=0

h=1.25m

1). v²-u²=2gh

v²-0=2×10×1.25

v²=25

v=√25

v=5m/s

3)momentum=mv=0.08×5=0.4Ns

4)K.E=mv²/2=0.08×25/2=1J

5)case before rebounding

at a height 1.25m, P.E.=mgh=0.08×10×1.25=1J

K.E.=0

after rebounding

u=5m/s

v=0

at ground,K.E=mu²/2=0.08×25/2=1

at 1m above,P.E=mgh=0.08×10×1 =0.8J, K.E=0

so 0.8 J energy is lost.