Well you didn’t give answer choices but this sounds like... he’s stereotyping? Stereotypes... ageism....
Answer:
(a) the time needs for her to cross the river is 2736.8 s.
(b) the distance takes to reach the other side of the river is 2490.5 m.
Explanation:
given information:
woman's speed, v₁ = 1.9 m/s
the wide of river, s = 5.2 km = 5200 m
river's current, v₂ = 0.91 m/s
(a) How much time does it take her to cross the river?
s = v t
s = the displacement (m)
v = speed (m/s)
t = time (s)
s = v t
t = s/v
= 5200/1.9
= 2736.8 s
(b) How far downstream will the river carry her by the time she reaches the other side of the river?
s = v t
= (0.91) (2736.8)
= 2490.5 m
Stairs don't HAVE any power. When you use the stairs, YOU have to provide all the power. I would use the elevator, because the machinery that runs it produces the power and I only have to stand there.
Explanation:
Elongation of the wire is:
ΔL = F L₀ / (E A)
where F is the force,
L₀ is the initial length,
E is Young's modulus,
and A is the cross sectional area.
ΔL = T (0.5 m) / ((2.0×10¹¹ Pa) (0.02 cm²) (1 m / 100 cm)²)
ΔL = T (1.25×10⁻⁶ m/N)
T = (80,000 N/m) ΔL
Draw a free body diagram of the mass at the bottom of the circle. There are two forces: tension force T pulling up and weight force mg pulling down.
Sum of forces in the centripetal direction:
∑F = ma
T − mg = mv²/r
T − mg = mω²r
T − (15 kg) (9.8 m/s²) = (15 kg) (2 rev/s × 2π rad/rev)² (0.5 m + ΔL)
T − 147 N = (2368.7 N/m) (0.5 m + ΔL)
Substitute:
(80,000 N/m) ΔL − 147 N = (2368.7 N/m) (0.5 m + ΔL)
(80,000 N/m) ΔL − 147 N = 1184.35 N + (2368.7 N/m) ΔL
(797631.3 N/m) ΔL = 1331.35 N
ΔL = 0.00167 m
ΔL = 1.67 mm
Answer:
The answer are as followed: B is the correct answer, hope that helps :)
