Answer:
8) 709.8875 J
9) The object is at 7.24375 m from the ground
10) Kinetic energy increases as the object falls.
Explanation:
We use the expression for the displacement h(t) as a function of time of an object experiencing free fall:
h(t) = hi - (g/2) t^2
hi being the initial position of the object (10m) above ground, g the acceleration of gravity (9.8 m/s^2), and t the time (in our case 0.75 seconds):
h(0.75) = 10 - 4/9 (0.75)^2 = 7.24375 m
This is the position of the 10 kg object after 0.75 seconds (answer for part 9)
Knowing this position we can calculate the potential energy of the object when it is at this height, using the formula:
U = m g h = 10kg * 9.8 (m/s^2) * 7.24375 m = 709.8875 J (answer for part 8)
Part 10)
the kinetic energy of the object increases as it gets closer to ground, since its velocity is increasing in magnitude because is being accelerated in its motion downwards.
Rate of change of momentum = impact force
(m*v-m*u)/t = F
4000*20/t = 80000 (note: v is zero as it stopped)
<span>soo, t = 1 sec</span>
Answer:
a) Total mass form, density and axis of rotation location are True
b) I = m r²
Explanation:
a) The moment of inertia is the inertia of the rotational movement is defined as
I = ∫ r² dm
Where r is the distance from the pivot point and m the difference in body mass
In general, mass is expressed through density
ρ = m / V
dm = ρ dV
From these two equations we can see that the moment of inertia depends on mass, density and distance
Let's examine the statements, the moment of inertia depends on
- Linear speed False
- Acceleration angular False
- Total mass form True
- density True
- axis of rotation location True
b) we calculate the moment of inertia of a particle
For a particle the mass is at a point whereby the integral is immediate, where the moment of inertia is
I = m r²
The answer is C guide and inspire good conduct
The second ball should strike at double the original t value
