When the ruler is broughı near the inetal knob, it repels electrons in the metal. Electrons move away froni the ruler and down the metal rod. The knob now has a positive charge. The thin pieces of metal foil at the bottom of the metal rod now have a negative charge.
Answer:
(c) 16 m/s²
Explanation:
The position is
.
The velocity is the first time-derivative of <em>r(t).</em>
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The acceleration is the first time-derivative of the velocity.

Since <em>a(t)</em> does not have the variable <em>t</em>, it is constant. Hence, at any time,

Its magnitude is 16 m/s².
The current passing through a circuit consisting of a battery of 12 V and resistor of 2 ohms is 6 Ampere
.
Explanation:
- Assume the wires are ideal with zero resistance.
- The current passing through the circuit will be
I = V/R = 12/2 = 6.000 A.
The time for the echo to return is directly proportional to the distance. vw = fλ. In a given medium under fixed conditions, vw is constant, so that there is a relationship between f and λ; the higher the frequency, the smaller the wavelength.
Let say for every 5 s of time interval the speed will remain constant
so it is given as
v(mi/h) 16 21 23 26 33 30 28
now we have to convert the speed into ft/s as it is given that 1 mi/h = 5280/3600 ft/s
so here we will have
v(ft/s) 23.5 30.8 33.73 38.13 48.4 44 41.1
now for each interval of 5 s we will have to find the distance cover for above interval of time



so here it will cover 1298.1 ft distance in 30 s interval of time