Answer:
The balloons have the same charge,
If they had opposite charges they would cling to one another.
Electrical energy = Power x time.
30 minutes = 0.5 hours.
Electical energy = 1200W x 0.5 hours = 600W/hour = 0.6kWh
Answer:
4
Explanation:
We are given that

K.E at x=0 m=20 J
K.E at x=3 m=11 J
We have to find the value of c.
By work energy theorem
Work done=Change in kinetic energy
W=
![W=[\frac{cx^2}{2}-x^3]^{3}_{0}](https://tex.z-dn.net/?f=W%3D%5B%5Cfrac%7Bcx%5E2%7D%7B2%7D-x%5E3%5D%5E%7B3%7D_%7B0%7D)






Answer:
a) 0.24 J
b) 2.1 cm
Explanation:
The work needed to stretch a spring is given by:

where x is the elongation:

We need to know the spring constant so we can calculate what is asked in question a.

so:


For b:
According to Hooke's law:

A force of 25N is pulling on the spring, so the spring pulls back with the same magnitude but in the opposite direction.
