Energy remains constant, so it doesn't change, which means it is conserved. The answer is a, the law of energy conservation.
Answer: Thus, the force is directed 72.5° above the horizontal.
Explanation:
The magnitude of the force, F = 15 N
let this force be detected at angle θ from the horizontal, then horizontal component of force is: F cos θ
and vertical component is F sin θ
Horizontal component is given,
F cos θ = 4.5 N
⇒15 N cos θ = 4.5 N
⇒ cos θ = 0.3
⇒ θ = cos⁻¹ 0.3 = 72.5°
The speed is 16.2 m/s
Explanation:
Assuming the runner is moving by uniform motion (=at constant velocity), then we can find his speed by using the equation:
where
v is the speed
d is the distance covered
t is the time elapsed
For the runner in this problem, we have:
The initial position is 10 m while the final position is 80 metres, so the distance covered is
d = 80 - 10 = 70 m
While the time elapsed to cover these 70 m is
t = 4.32 s
Therefore, substituting into the equation, we find the speed:
Learn more about speed:
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The answer is 54.675 J
<span>The kinetic energy (Ke) of an object is the product of half of its mass (m) and the square of its velocity (v²):
</span>Ke = 1/2 m * v²
We have:
Ke = ?
m = 15 kg
v = 2.7 m/s
_____
Ke = 1/2 * 15 kg * (2.7 m/s)² = 1/2 * 15 kg * 7.29 m²/s² = 54.675 kg * m²/s²
Ke = 54.675 J
Answer:
A = B = C > D
Explanation:
Work done to stop the disc is given as
so we have
(a) –2 rad/s, 5 rad/s;
(b) 2 rad/s, 5 rad/s;
(c) –2 rad/s, –5 rad/s; and
(d) 2 rad/s, –5 rad/s.
So we have
so we have
A = B = C > D