Which scenario involves kinetic energy transforming into potential energy? A. a book lying on a shelf B. a train traveling at a
1 answer:
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Answer:
a) W = 46.8 J and b) v = 3.84 m/s
Explanation:
The energy work theorem states that the work done on the system is equal to the variation of the kinetic energy
W = ΔK = -K₀
a) work is the scalar product of force by distance
W = F . d
Bold indicates vectors. In this case the dog applies a force in the direction of the displacement, so the angle between the force and the displacement is zero, therefore, the scalar product is reduced to the ordinary product.
W = F d cos θ
W = 39.0 1.20 cos 0
W = 46.8 J
b) zero initial kinetic language because the package is stopped
W - =
-K₀
W - fr d= ½ m v² - 0
W - μ N d = ½ m v
on the horizontal surface using Newton's second law
N-W = 0
N = W = mg
W - μ mg d = ½ m v
v² = (W -μ mg d) 2/m
v = √(W -μ mg d) 2/m
v = √[(46.8 - 0.30 4.30 9.8 1.20) 2/4.3 ]
v = √(31.63 2/4.3)
v = 3.84 m/s
Answer:
6.32s
Explanation:
Given parameters:
Length of track and distance covered = 200m
Acceleration = 10m/s²
Unknown:
Time taken to cover the track = ?
Solution:
To solve this problem, we apply one of the motion equations as shown below:
S = ut + at²
S is the distance covered
t is the time taken
a the acceleration
u is the initial velocity
The initial velocity of Superman is 0;
So;
S = at²
200 = x 10 x t²
200 = 5t²
t² = 40
t = 6.32s