Answer:
u = 25 m/s
Explanation:
given,
length of skid = 93 m
coefficient of friction = 0.35
final velocity = 0 m/s
initial velocity = ?
force here is friction f = μ mg
F = ma
now com paring
-μ mg = m a
a = - μ g
a = - 0.35 x 9.8
a = -3.43 m/s²
we know,
v² = u² + 2 a s
0 = u² - 2 x 3.43 x 93
u² = 637.98
u = 25.26 m/s
u = 25 m/s (two significant figure)
Answer:
Current = 8696 A
Fraction of power lost =
= 0.151
Explanation:
Electric power is given by

where I is the current and V is the voltage.

Using values from the question,

The power loss is given by

where R is the resistance of the wire. From the question, the wire has a resistance of
per km. Since resistance is proportional to length, the resistance of the wire is

Hence,

The fraction lost = 