Answer:
a) W = 5360 J b) μ = 0.29
Explanation:
a) The work is, bold indicate vectors
W = F. d = F d cos T
W = 40 268 cos 60
W = 5360 J
b) The force of friction and opposes the movement of the body and if the speed of the body is constant implies that the external force in the direction of the movement is equal to the force of friction, or which work is the same
= -5360J
The negative sign is because the force of friction is contrary to the direction of movement
c) Let's write the work of the friction force
= fr d cos 180
fr = μ N
Since the body is on a horizontal surface, from Newton's second law on the Y axis
N-W = 0
N = W
fr = μ W
= - μ W d
μ = - / W d
μ = - (-5360) / 69 268
μ = 0.29
6. "The electric field caused by an electron is weakest near the electron" is FALSE.
7. "An electric field becomes weaker as distance from the electron increase" is TRUE.
<u>Explanation:</u>
The "electrical field" covers the electrical charge and exerts, attracts or repels other charges in the field.The electric field caused by an electron is strongest near the electron while it become weak as distance from the electron increase.
The reason behind is, at a point the direction of the field line is at that point the direction of the field. The relative magnitude of the electric field will be proportional to the field line density. The field is strongest where the field lines are near together and when the field lines are at increasing distance the field is weakest.
Can a measurement be exact? No
From the Hooke's law , the extension force of an elastic material is directly proportional to the extension.
That is, F = k e, where F is the force , k is the constant and e is the extension
F = 10 × 10 = 100 N
e = 1mm or 0.001 m
Hence, k = F/e
= 100 N/ 0.001
= 100000 N/m or 100 N/mm
