Answer:
We use X-rays to help the injured, Radiowaves to communicate or entertain, and Visible light to see.
Explanation:
voltage = current × resistance
5.
12 V = 4.2 A × resistance
resistance = 12 V / 4.2 A = 2.857142857... Ohm
FYI :
4.2 A would be a lot for a small electronic device like a CD player. that would be 12×4.2 = 50.4 Watt, and the CD player would get really hot.
6.
120 V = current × 12 Ohm
current = 120 V / 12 Ohm = 10 A
We are given with the data that says the probability that a battery will last 10 hr or more is 0.8 and the probability <span>that it will last 15 hr or more is 0.11. In this case, the probability that the battery lasts at least 10 hours and even 15 hrs more is 0.11 / 0.8 or equal to 13.75 percent.</span>
(a) 392 N/m
Hook's law states that:
(1)
where
F is the force exerted on the spring
k is the spring constant
is the stretching/compression of the spring
In this problem:
- The force exerted on the spring is equal to the weight of the block attached to the spring:
- The stretching of the spring is
Solving eq.(1) for k, we find the spring constant:
(b) 17.5 cm
If a block of m = 3.0 kg is attached to the spring, the new force applied is
And so, the stretch of the spring is
And since the initial lenght of the spring is
The final length will be
