Answer:
Magnification will be equal to 3
Explanation:
We have given focal length of the converging lens 
Focal length of the diverging lens 
Object is placed 40 cm to the length of the converging lens d = 40 cm
Combination of the focal length will be equal to


F = 60 cm
So combination of the focal length will be 60 cm
Magnification is given by

So magnification will be equal to 3
Answer:
If velocity is doubled, Kinetic Energy increases by 4 times. Kinetic energy of a body is the energy possessed by it, by virtue of its motion, i.e. if the body is moving it will always have kinetic energy.Nov 1, 2018
Explanation:
Answer:
Part a)

Part b)

Explanation:
Part a)
Level of sound = 75 dB
now we know that

here we know that

now we have


Part b)
Intensity of sound wave is given as

here we know that

so we have


now we know



now we have


The momentum of the rolling ball will have less momentum than before the collision and the stationary ball will have more momentum after the collusion.