If an object has a mass of 50 kilograms, what would it weigh on uranus, where the acceleration due to gravity is 10.5 meters/second2?

You can use the formula:

Weight = mass × gravity
W = 50 kg * 10.5 m/s^2
W = 525 kg * m/s^2 or 525 N
 hope this helps :)

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.