First of all, I is proportional V according to the Ohm's Law. R is merely a constant you need to obtain an equation. However, it is true that R changes with temperature and pressure, therefore Ohm's Law is only applicable in an invariable environment. Also this constant R is different for different materials.
So, do not get confused.
Ohm's law is not a universal law, please remember that as well. Some materials do not follow it and we call them non-ohmic conductors. I hope I helped! ^-^
Answer:
159.38 Watts
Explanation:
Initially;
- Mass on the spring is 8.5 kg
- Therefore, compression force is 85 N
- Compression distance is 15 cm or 0.15 m
But;
F = kx
where F is the force of compression, k is the spring constant and x is the compression distance.
Thus;
k = F/x
= 85 N ÷0.15
= 566.67 N/m
We are required to determine the power needed to stretch the same spring for 1.5 m in 4 secs.
Power = Work done ÷ time
Work done is given by 0.5kx²
Therefore;
Power = 0.5kx²÷ t
= (0.5×566.67 N/m × 1.5² ) ÷ 4 seconds
= 159.38 Watts
Thus, the power needed is 159.38 watts
She is traveling at a constant speed.
Answer:
Explanation:
a) The magnitude of the net force on the student = 0 N since the student is standing still on level ground and upward reaction force = downward force.
b) the magnitude of the contact force on the student by the backpack = 80 N since the student was backing the backpack
c) the magnitude of the contact force o the student by the ground = 550 N + 80 N = 630 N reactional force on the student
velocity is magnitude and direction. its unit is meter per second
