Answer:
Option (b) is correct.
Explanation:
The motion under the influence of gravity is called projectile motion.
The acceleration due to gravity is constant through out the motion and it is always acting downwards.
When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.
Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.
Option (b) is correct.
Answer:
.
Explanation:
By Newton's Second Law, the acceleration
of an object is proportional to the net force
on it. In particular, if the mass of the object is
, then
.
Rewrite this equation to obtain:
.
In this case, the assumption is that the
force is the only force that is acting on the object. Hence, the net force
on the object would also be
Make sure that all values are in their standard units. Forces should be in Newtons (same as
, and the acceleration of the object should be in meters-per-second-squared (
). Apply the equation
to find the mass of the object.
.