A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density.
Weight = (mass) x (gravity)
70 N = (mass) x (9.8 m/s²)
Divide each side by (9.8 m/s²) , and you have
mass = 70 N / 9.8 m/s² = 7.14 kg.
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Mass on the moon:
Mass doesn't change. It's a number that belongs to the bowling ball,
no matter where the ball goes. If the mass of the bowling ball is 7.14 kg
anywhere, then it's 7.14 kg everywhere ... on Earth, on the moon, on Mars, rolling around in the trunk of my car, or floating in intergalactic space.
However, WEIGHT depends on the gravity wherever the ball happens to be
at the moment.
The acceleration of gravity on the moon is 1.622 m/s².
So the WEIGHT of the ball on the moon is
(7.14 kg) x (1.622 m/s²) = 11.58 Newtons
That's only about 16% of its weight on Earth.
(A) The impeller blades are worn or slipping on the shaft
(d) option is right answer