C is the correct answer but the best possible answer is that work is done when a force is imposed on an object and the object moves in the same direction as the force
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Answer: A
Explanation: Neglecting air resistance every object will return to the ground at the same interval regardless of their weights, we can say that the objects are undergoing free falls, they are falling under the sole of gravity.
No matter the weight of the objects or the elevation, without significant air resistance, they will reach the ground at the same time.
Answer:
U = 25 J
Explanation:
The energy in a set of charges is given by
U = 
in this case we have three charges of equal magnitude
q = q₁ = q₂ = q₃
with the configuration of an equilateral triangle all distances are worth
d = a
U = k (
)
we substitute
15 = k q² (3 / a)
k q² /a = 5
For the second configuration a load is moved to the measured point of the other two
d₁₃ = a
The distance to charge 2 that is at the midpoint of the other two is
d₁₂ = d₂₃ = a / 2
U = k (\frac{q_1q_2}{ r_1_2 } + \frac{q_1q_3}{r_1_3} + \frac{q_2q_3}{r_2_3})
U = k q² (
)
U = (kq² /a) 5
substituting
U = 5 5
U = 25 J
Answer:
The average velocity is 8 unit per sec
Explanation:
Given as :
The Distance x = 20 - 4t² unit
Change in time Δt = ( 2 - 0 ) s = 2 s
Let the velocity = V unit/s
∴ V = 
Or, V = - 8t unit/s
Now velocity at t = 0
V1 = - 8 × 0 = 0 unit/s
And velocity at t = 2 sec
V2 = - 8 × 2 = - 16
So, Average velocity =
=
= -8
Or,
= 8 unit/sec
Hence The average velocity is 8 unit per sec Answer