Answer:
A) 31 kJ
B) 1.92 KJ
C) 40 , 2.48
Explanation:
weight of person ( m ) = 79 kg
height of jump ( h ) = 0.510 m
Compression of joint material ( d ) = 1.30 cm ≈ 0.013 m
A) calculate the force
Fd = mgh
F = mgh / d
W = mg
F(net) = W + F = mg ( 1 + 
= 79 * 9.81 ( 1 + (0.51 / 0.013) )
= 774.99 ( 40.231 ) ≈ 31 KJ
B) calculate the force when the stopping distance = 0.345 m
d = 0.345 m
Fd = mgh hence F = mgh / d
F(net) = W + F = mg ( 1 + 
= 79 * 9.81 ( 1 + (0.51 / 0.345) )
= 774.99 ( 2.478 ) = 1.92 KJ
C) Ratio of force in part a with weight of person
= 31000 / ( 79 * 9.81 ) = 31000 / 774.99 = 40
Ratio of force in part b with weight of person
= 1920 / 774.99 = 2.48
Answer:
(A) 
Explanation:
The net force perpendicular to the surface of the incline is the sum of the gravity force component, which is mgcos(theta), and the reactionary normal force caused by the surface of the incline. The sum is F_N - mgcos(theta) and is usually 0 which is why the object is not moving perpendicularly to the surface of the incline.
Answer:
i believe the answer is true
Explanation:
everything was created in the big bang
The gravitational potential energy U is defined as the product of mass m, the acceleration of gravity g and the height of object h.

We do not have the mass of the hiker. But we know that its W weight is:

Where

So:
.
So:

J
The hiker has gained 30,000 J of energy
Answer:

Explanation:
Let assume that one end of the spring is attached to the ground. The speed of the metal block when hits the relaxed vertical spring is:


The maximum compression of the spring is calculated by using the Principle of Energy Conservation:

After some algebraic handling, a second-order polynomial is formed:


The roots of the polynomial are, respectively:


The first root is the only solution that is physically reasonable. Then, the elongation of the spring is:

The maximum height that the block reaches after rebound is:

