on touching electroscope gets positively charged, so answer is B. conduction
Answer:

Explanation:
The formula for force is:

If we rearrange the formula to solve for a (acceleration), the formula becomes

The force is 68 Newtons. Let's convert the units to make the problem easier later on. 1 N is equal to 1 kg*m/s², so the force of 68 N is equal to 68 kg*m/s².
The mass is 2 kilograms.

Substitute the values into the formula.

Divide. Note that the kilograms will cancel each other out (hence why we changed the units).


The acceleration is<u> </u><u>34 meters per second squared.</u>
Answer: When an ambulance passes with its siren blaring, you hear the pitch of the siren change: as it approaches, the siren’s pitch sounds higher than when it is moving away from you. This change is a common physical demonstration of the Doppler effect.
Explanation: