Answer:
the answers are
W = 1271.256 J
= 361.81 J
Explanation:
The mass of the trunk (m) = 46kg
angle between the ramp and the horizontal (θ) = 42°
The trunk is pulled at a displacement (d) up the ramp = 3m
The coefficient of kinetic friction between the trunk and the ramp = 0.36
The trunk is moving with a constant velocity therefore the net force on it is zero, therefore the force required to move the trunk must be equal to the summation of forces opposing the trunk
The two forces opposing the trunk are
- the gravitational force directed down the ramp
and - the frictional force between the ramp and the trunk

We have to calculate the machine's force which is equal to sum of the

=
θ
μ× N
N = mgcosθ
μ
θ
F = mg (sinθ + μcosθ)
F = 46× 9.8 (sin42 + 0.36×cos42)
F= 450.8 (0.67 +0.27)
F = 450.8 × 0.94
F = 423.752N
to calculate the workdone on the trunk by the machine force
The workdone on the trunk is = W = F × dcosΘ
Θ = 0° because the trunk is directed parallel to the ramp
W =423.752× 3 cos 0
W = 423.752 ×3
W = 1271.256 J
(b) the increase in thermal energy of the trunk and the ramp
Friction converts mechanical energy into thermal energy, so multiplying the frictional force with the distance gives the thermal energy generated by the trunk
× d
= μ
θ ×d
= 0.36 ×46×9.8×cos42×3
= 361.81 J
Answer: c) Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed.
Hey
On Earth, you can move or you can not move. if you are moving 50 mph that means relative to Earth (not the Andromeda galaxy). When you start moving (accelerating) you are now moving relative to Earth. when you start slowing down (decelerating [most scientists just say you have negative acceleration]) you are starting to match your velocity to Earth's velocity.
Hope it helped and made any sence at all.
Spiky bob your answerer.
Answer: option D) 42.4 N
The weight of the frame is balanced by the vertical component of tension.
W = T sin θ + T sin θ = 2 T sin θ
The tension in each cable is T = 30 N
Angle made by the cables with the horizontal, θ = 45°
⇒ W = 2×30 N × sin 45° = 2 × 30 N × 0.707 = 42.4 N
Hence, the weight of the frame is 42.4 N. Correct option is D.
Answer:

Explanation:
Velocity of wave in stretched string is given by the formula

here we know that
T = 4 N
also we know that linear mass density is given as

so we have

now the tension in the string is double
so the velocity is given as

