Answer:
D) Heavier objects need a greater force to accelerate according to F=ma.
Explanation:
The force of gravity acting on an object is equal to:
F = mg
where m is the mass of the object and g is the acceleration due to gravity. According to the formula, heavier objects (objects with greater mass, m) have a larger force of gravity acting on them.
However, the acceleration of an object towards the ground is given by:
therefore, we see that if the object is heavier (larger mass, m), the force of gravity (F) must also be larger in order to have the same acceleration a.
We have the equation of motion , where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.
Here s = 300 m, u = 0 m/s, a = 9.81
Substituting
Now we have v = u+at, where v is the final velocity
Here u = 0 m/s, a= 9.81 and t = 7.82 seconds
Substituting
v = 0+9.8*7.82 = 76.68 m/s
The speed with which the penny strikes the ground = 76.68 m/s.
As per the question, the mass of meteorite [ m]= 50 kg
The velocity of the meteorite [v] = 1000 m/s
When the meteorite falls on the ground, it will give whole of its kinetic energy to earth.
We are asked to calculate the gain in kinetic energy of earth.
The kinetic energy of meteorite is calculated as -
Here, J stands for Joule which is the S.I unit of energy.