Answer:
Four times higher
Explanation:
F- G (m1 x m2)/ r^2
if r 1 = 2 and r 2 = 1 therefore F = G (m1 x m2)/ 1^2 is 4 times higher than
2^2 since G and m1 and m2 remained the same
Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
Answer:
There is an inward force acting on the can
Explanation:
This inward force is known as Centripetal force and it is responsible for making the can whirl on the end of a string in circle and it is also directed towards the center around which the can is moving.
In Linear motion the swimmer swims