Answer:
The answer is the 1st one
Answer:
The work done on the box is 100 Nm
The power is 20 Nm/s
Explanation:
There is a force 25 newtons moves a box a distance of 4 meters in
5 seconds
The work done on the box is the product of the force and the distance
that the box moves ⇒ <em>work = force × distance</em>
The force = 25 newtons
the distance = 4 meters
Work = 25 × 4 = 100 NM
<em>The work done on the box is 100 Nm</em>
<em></em>
The force moves the box 4 meters in 5 seconds
The power is the rate of work
<em>The power = work ÷ time</em>
The work = 100 Nm
The time = 5 seconds
The power = 100 ÷ 5 = 20 Nm/s
<em>The power is 20 Nm/s</em>
Answer:
(a) The force between them quadruples
Explanation:
According to coulomb's law, initial force between the two charged objects is given as;

where;
k is coulomb's constant
q₁ is the charge on the first object
q₂ is the charge on the second object
r is the distance between the two objects
When the charges on both objects are doubled, then;
q₁ = 2q₁
q₂ = 2q₂
Force between the two charged objects will become

Therefore, the force between them quadruples
Ya because they’re are both 50 liters
Answer:
Time taken by A and B is 1.2 hr.
Explanation:
Given that
Time taken by tank when all(A+B+C) are open = 1 hr
Time taken by tank when A+C are open = 1.5 hr
Time taken by tank when B+C are open = 2 hr
If we treat as filling of tank is a work then
Work = time x rate
Lets take work is 1 unit
1 = 1(1/a+1/b+1/c) ---------1
1 = 1.5(1/a+1/c) ----------2
1 = 2(1/b+1/c) --------3
From equation 1 and 3
1=1(1/a+1/2)
a=2
Form equation 2
1 = 1.5(1/2+1/c)
c=6
From equation 3
1 = 2(1/b+1/6)
b=3
So time taken by
A is alone to fill tank is 2 hr
B is alone to fill tank is 3 hr
C is alone to fill tank is 6 hr
So 
Time taken by A and B is 1.2 hr.