Just solve for a in this equation
Vf=Vi*A
Answer:3.49 m/s
Explanation:
Given
Speed of marble at Bottom 
Diameter of loop 
As Energy is conserved therefore Energy at top is equal to energy at bottom

,where
is the velocity at bottom







The answer to your question is A
Answer:
The velocity of the leaf relative to the jogger is 5 m/s.
Explanation:
Given that,
Velocity of jogger wrt to the ground, 
velocity of leaf wrt the ground, 
We need to find the velocity of the leaf relative to the jogger. Let it is equal to V. So, it is given by :

So, the velocity of the leaf relative to the jogger is 5 m/s. Hence, this is the required solution.
The red box must way more. Gravitational potential energy is the product of a an objects mass times the acceleration due to gravity (which is constant on earth) times its height. Since the objects are on the same shelf they are at the same height, and since gravitational acceleration is constant as long as we stay on planet earth, then the mass is the only possible thing that could have changed. This means that the red box must weigh more than the blue box.