Answer
given,
mass of the package = 12 kg
slides down distance = 2 m
angle of inclination = 53.0°
coefficient of kinetic friction = 0.4
a) work done on the package by friction is
W_f = -μk R d
= -μk (mg cos 53°)(2.0)
=-(0.4)(8.0 )(9.8)(cos 53°)(2.0)
= -37.75 J
b)
work done on the package by gravity is
W_g = m (g sin 53°) d
= (8.0 )(9.8 )(sin 53°)(2.0 )
=125.23 J
c)
the work done on the package by the normal force is
W_n = 0
d)
the net work done on the package is
W = -37.75 + 125.23 + 0
W = 87.84 J
Answer:
power, P = 90 hp
Explanation:
It is given that,
Mass of the car, m = 1500 kg
Initial velocity of car, u = 0
Final velocity of car, v = 25 m/s
Time taken, t = 7 s
We need to find the average power delivered by the engine. Work done divided by total time taken is called power delivered by the engine. It is given by :
According to work- energy theorem, the change in kinetic energy of the energy is equal to work done i.e.
P = 66964.28 watts
Since, 1 hp = 746 W
So, P = 89.76 hp
or
P = 90 hp
So, the average power delivered by the engine is 90 hp. Hence, the correct option is (E) " 90 hp".
Answer:
Distance of Earth from the Sun has nothing to do with the seasons only the tilt is responsible for the change in seasons.
Explanation:
The Earth's tilt does cause the seasons but the distance from the sun and has nothing to do with the change in seasons. In June, when the Northern Hemisphere is tilted in the direction of the Sun during the Northern Hemisphere summer the Earth is actually farthest from the Sun. In January, when the Southern Hemisphere is tilted in the direction of the Sun during the Northern Hemisphere winter the Earth is actually closest to the Sun. This is caused due to the elliptical orbit of the Earth. So, distance of Earth from the Sun has nothing to do with the seasons.
Answer:
3.9 seconds
Explanation:
Use constant acceleration equation:
y = y₀ + v₀ t + ½ at²
where y is the final position,
y₀ is the initial position,
v₀ is the initial velocity,
a is the acceleration,
and t is time.
Given:
y = 0 m
y₀ = 15 m
v₀ = 15 m/s
a = -9.8 m/s²
Substituting values:
0 = 15 + 15t + ½ (-9.8) t²
0 = 15 + 15t − 4.9t²
0 = 4.9t² − 15t − 15
Solve with quadratic formula:
t = [ -b ± √(b² − 4ac) ] / 2a
t = [ 15 ± √((-15)² − 4(4.9)(-15)) ] / 2(4.9)
t = [ 15 ± √(225 + 294) ] / 9.8
t = (15 ± √519) / 9.8
t = -0.79 or 3.9
It takes 3.9 seconds for the stone to reach the bottom of the well.
The negative answer is the time it takes the stone to travel from the bottom of the well up to the top of the well.
Answer:
28500
Explanation:
Force equation - F = m * a
F = 950 * 30
F = 28500
