Answer:
I = 4.75 A
Explanation:
To find the current in the wire you use the following relation:
(1)
E: electric field E(t)=0.0004t2−0.0001t+0.0004
ρ: resistivity of the material = 2.75×10−8 ohm-meters
J: current density
The current density is also given by:
(2)
I: current
A: cross area of the wire = π(d/2)^2
d: diameter of the wire = 0.205 cm = 0.00205 m
You replace the equation (2) into the equation (1), and you solve for the current I:
Next, you replace for all variables:
hence, the current in the wire is 4.75A
Answer:
W = 68.6 N
Explanation:
Given that,
Force acting on a right side = 30 N
Mass of the object, m = 7 kg
The force of friction acting on the car = 3 N
We need to find the weight of the object.
The weight of an object is given by :
W = mg
Substitute all the values,
W = 7 × 9.8
W = 68.6 N
So, the weight of the object is 68.6 N.
To the right, if you push something left the friction is to the right
Answer:
1.2 × 10^27 neutrons
Explanation:
If one neutron = 1.67 × 10^-27 kg
then in 2kg...the number of neutrons
; 2 ÷ 1.67 × 10^-27
There are.... 1.2 × 10^27 neutrons
