Answer: 3 m.
Explanation:
Neglecting the mass of the seesaw, in order the seesaw to be balanced, the sum of the torques created by gravity acting on both children must be 0.
As we are asked to locate Jack at some distance from the fulcrum, we can take torques regarding the fulcrum, which is located at just in the middle of the length of the seesaw.
If we choose the counterclockwise direction as positive, we can write the torque equation as follows (assuming that Jill sits at the left end of the seesaw):
mJill* 5m -mJack* d = 0
60 kg*5 m -100 kg* d =0
Solving for d:
d = 3 m.
Answer:

Explanation:
Given that
The speed of the airplane ,v= 142 m/s
The speed of the air ,u = 30 m/s
Lets take angle make by airplane from east direction towards north direction is θ .
Now by using diagram ,we can say that

Now by putting the values in the above equation we get



Therefore the angle will be 12.19° .
Some fruits and vegetables sink in water and some float in water. None swim.
Answer:
The amplitude of the resultant wave will be 0.
Explanation:
Suppose the first wave has an amplitude of A. Its angle is given as wt.
The second way will also have the same amplitude as that of first.
After the reflection, a phase shift of π is added So the wave is given as

Adding the two waves give

So the amplitude of the resultant wave will be 0.
The period is the reciprocal of the frequency. (1 divided by it)
Frequency = 261 / 1 second
Period = 1/261 second
= 0.00383... second (rounded)