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Q15)HELP ME ON THESE QUESTIONS PLS
15 22 32 of n10 variant 12
16 19 34 of J11 variant 12
waiting for quick reply pls with details on this and my previous asked questions on page 38pls lesco where are u
At terminal velocity, weight = air resistance
so mg = kv
And v = mg/k
Now substitute v with mg/k in 1/2 mv^2 formula to get the answer.
Q22) You want high sensitivity for small masses, i.e. a big change in extension for smaller masses. This means a lower value of 'k' is needed for the smaller masses. The rigid box is there to prevent external forces like wind from pushing the masses on the spring. Also, when you have larger masses on the spring, then you need a higher value of 'k', i.e. a small extension for a large load. So the answer would be A.
Q32)
A and B are wrong because the e.m.f. can't decrease, its the energy being provided by the battery.
Also, VT = E - Ir (terminal voltage i.e. voltage across the battery is equal to e.m.f. - internal resistance * current).
From this equation, we can confirm that answer C is correct.
S11/12
Q16) Assume the length of the rod to be 1m. You know that the weight lies exactly in the middle, so each side is 0.5m apart. If you take the wall to be the pivot, then you can form an equation,
F sin 30 * 1 = 0.5 * 10
F = 10.0 N
Q19)
Work = force * distance in direction of force
10 = 0.005 * force
force = 2000 N
Q34) The answer to this one is a fact, you have to learn it. The e.m.f. depends on both r and R.
A is wrong because using the equation VT = E - Ir, the terminal voltage will change.
B is wrong because the current would decrease, not increase.
C is wrong because the e.m.f. of the battery can't change.
D is a correct statement. You can verify this yourself using P = I^2 * R
