Do you have a diagram or anything?
Answer:
(d) 9 × 10^{3] J
Explanation:
from the question we are given the following:
weight of the man = 6.0 × 10 ^ {2} N
average speed (v) = 3 m/s
time (t) = 3 s
potential energy (U) = ?
We can calculate the increase in potential energy of the man by applying the formula below
increase in potential energy = P₂ - P₁
where
- P₁ is the initial potential energy
- P₂ is the final potential energy
- Potential energy = mass x acceleration due to gravity x height
From physic we know that weight = mass x acceleration due to gravity
- We should take note that the distance in this case is also our height, and we can get it from the formula distance = velocity x time
- Distance = 3 x 5 = 15 meters
- Initial potential energy P₁ is zero because the person was initially in motion and potential energy is the energy at rest.
therefore
potential energy = 6.0 × 10 ^ {2} × 15 = 9 × 10^{3] J
Answer:
323 m/s²
Explanation:
Given:
x₀ = 0 m
y₀ = 0 m
x = 29500 cos 65°
y = 29500 sin 65°
v₀x = 1810 cos 20°
v₀y = 1810 sin 20°
t = 9.20
Find:
ax, ay, θ
First, in the x direction:
x = x₀ + v₀ t + ½ at²
29500 cos 32° = 0 + (1810 cos 20°) (9.20) + ½ ax (9.20)²
25017 = 15648 + 42.32 ax
ax ≈ 221.4
And in the y direction:
y = y₀ + v₀ t + ½ at²
29500 sin 32° = 0 + (1810 sin 20°) (9.20) + ½ ay (9.20)²
15633 = 5695 + 42.32 ay
ay ≈ 234.8
Therefore, the magnitude of the acceleration is:
a² = ax² + ay²
a² = (221.4)² + (234.8)²
a ≈ 322.7
Rounded to 3 significant figures, the magnitude of the acceleration is approximately 323 m/s².
Answer:
B. positive; negative.
Explanation:
From the viewpoint of Principle of Energy Conservation and Work-Energy Theorem, we notice that gravity represents a conservative force, associated with gravitational potential energy, whereas air resistance is a non-conservative force, associated with dissipated work. Therefore, the work done by gravity is positive and work done by air resistance is negative. Therefore, the correct answer is B.
