Answer:
m = 1 kg
Explanation:
Given that,
The force constant of the spring, k = 39.5 N/m
The frequency of oscillation, f = 1 Hz
The frequency of oscillation is given by the formula as formula as follows :

So, the mass that is attached to the spring is 1 kg.
Answer:
Time = 0.55 s
Height = 8.3 m
Explanation:
The ball is dropped and therefore has an initial velocity of 0. Its acceleration, g, is directed downward in the same direction as its displacement,
.
The dart is thrown up in which case acceleration, g, acts downward in an opposite direction to its displacement,
. Both collide after travelling for a time period, t. Let the height of the dart from the ground at collision be
and the distance travelled by the ball measured from the top be
.
It follows that
.
Applying the equation of motion to each body (h = v_0t + 0.5at^2),
Ball:
(since
.)

Dart:
(the acceleration is opposite to the displacement, hence the negative sign)

But




The height of the collision is the height of the dart above the ground,
.




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Answer:
(B) 1.23 x 10⁴ J
Explanation:
Given;
radius of the sphere, r = 7.0 m
diameter of the sphere, d = 2r = 14.0 m
mass of the person sitting on the sphere, m = 90.0 kg
The gravitational potential energy of the person is given by;
P.E = mgh
where;
g is acceleration due to gravity = 9.8 m/s²
h is the height above the ground level = d = 14.0 m
P.E = mgh
P.E = (90)(9.8)(14)
P.E = 12348 J
P.E = 1.2348 x 10⁴ J
Therefore, the gravitational potential energy of the person is 1.2348 x 10⁴ J