Since opinions are different, I think, it's better to verify the result by experiment. Of course, there will be effect of internal resistance. I don't have a good lab in my school. Someone pls try.

Maximum tension on A's  tail = 30N

Weight of monkey B = 2kg

Maximum acceleration of monkey B = (30N - 2 * 10)/2

                                                                 = 5m/s^2

So maximum  total force monkey A should apply = (5+2)*10+(5+2)*5

                                                                                        = 105N

This is the maximum value. It can be any value above 70N.

So the answer is C

In the question both batteries are connected in parallel with both positive on one side and negetive on the other side. So they are not opposing each other but helping each other and sharing the load equally. From fig-1 it is clear that potential difference across the resistor is 1V. So the current through it is 1A. This current will be shared by both batteries equally. ie 0.5A each.

Now suppose  the circuit is like given in fig-2. Here the battery positive and negetive are opposing  each other and the pd across the resistor becomes zero and  so no current.

If the batteries are connected in series as shown in fig-3, we all know current will be 2A.

@kitty007

You are right. I understood the question wrongly

We know that when the propeller is underwater boat moves. The atmosphere is also like river. Only difference is that density is very less. So the force also will be less but reaction will be there. Here it is not same system. Action is on atmosphere and reaction is on boat.           

The fan while pushing the air will get a reaction which will be passed to the boat through the base of the fan.

The fan should be blowing the air in opposite direction of boats movement.

YES

answer is option B =)

Tension in the string = m ( g - g/4 )

                                      = 3mg/4

distance travelled      = -d

work done                   = 3mg/4 . (-d)

                                      = -3mgd/4

This energy is lost as friction between the string and the holding mechanism.

When temperature increases why the resistance of a metal increases?

@ Bhim

Your answer is perfect and your solution is eligant!  Hats off !!!

I did it like this.

Let   be the angular displacement when both hands come together and t be the time taken for this.

  = 2 t / 12                         ( hour hand )

2 +  = 2 t / 1                ( minute hand )

subtituting

2 + 2 t / 12 = 2 t / 1 

1 + t / 12 = t

So t = 12/11 hours

I understand that in interference there is no destruction of energy but only redistribution. I think that is why we have brighter and darker spots/lines. The total energy remains same.

At 12:00:00 hrs both minute hand and hour hand are together. After what time ( correct to seconds )these hands will come together again ? Pls provide the work out.