A 28 kg rock falls freely near the surface of the Earth. Approximately how much gravitational force is exerted by the Earth on the rock? A. 2.8 N B. 280 N C. 28 N D. 2,800 N

Answer :Force is exerted by the Earth on the rock is 280 N .

Given :

Mass of rock falling falling , m = 28 kg .

Acceleration due to gravity , .

We need to find the force exerted by the earth on the rock .

Let force exerted be F .

Now , we know by Newton's Law Of Motion .

F = ma     .......( 1 )

Here , m is  mass and a is acceleration in this case it is .

Putting all these value in equation( 1 ) we get ,

Therefore, this is the required solution .

b. a lightning bug, plug of grass, and a worm