A boat is traveling upstream at 14 km/h with respect to the water of a river. The water itself is flowing at 9 km/h with respect
1 answer:
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Answer:
Q1: 3.2km
Q2: 4.8K
Explanation:
Q1:
So db is the distance of bird, and dr is the distance of runner
db = 2vr and the distance of bird is going to be 2 times greater than the runner.
formulas: db = 2vr & db = 2dr
- db = 2dr
- L + (L - x) = 2x
- 2L - x = 2x
- 2L = 3x
- x =
L
Insert it in x = L
(2.4km) = 1.6km
Now we use formula db = 2dr
- db = 2L - x
- db = 2(2.4km) - 1.6km
- <u>db = 3.2km</u>
Q2:
Formulas: Vr = L /Δt & Vb = db/Δt
- Vr = L/ Δt ⇒ Δt =
(Km cancel each other)
- Vb = db/Δt ⇒ db = VbΔt
- 13.6km/hr
- <u>4.8km</u>
(hr cancel each other)
Hope it helps you :)
Answer:
Explanation:
A mass of 700 kg will exert a force of
700 x 9.8
= 6860 N.
Amount of compression x = 4 cm
= 4 x 10⁻² m
Force constant K = force of compression / compression
= 6860 / 4 x 10⁻²
= 1715 x 10² Nm⁻¹.
Let us take compression of r at any moment
Restoring force by spring
= k r
Force required to compress = kr
Let it is compressed by small length dr during which force will remain constant.
Work done
dW = Force x displacement
= -kr -dr
= kr dr
Work done to compress by length d
for it r ranges from 0 to -d
Integrating on both sides
W =
= [ kr²/2]₀^-4
= 1/2 kX16X10⁻⁴
= .5 x 1715 x 10² x 16 x 10⁻⁴
= 137.20 J