Let F = the downstream speed of the water.
<span>Then the boat's upstream speed is: 15 - F </span>
<span>The boat's downstream speed is: 15 + F </span>
<span>Assume both the journeys mentioned take T hours, then using "speed x time = distance" we get: </span>
<span>Downstream journey: (15 + F)T = 140 </span>
<span>Upstream journey: (15 - F)T = 35 </span>
<span>Add the two formulae together: </span>
<span>(15 + F)T + (15 - F)T = 140 + 35 </span>
<span>15T + FT + 15T - FT = 175 </span>
<span>30T = 175 </span>
<span>T = 35/6 </span>
<span>Use one of the equations to find F: </span>
<span>(15 + F)T = 140 </span>
<span>15 + F = 140/T </span>
<span>F = 140/T - 15 </span>
<span>F = 140/(35/6) - 15 </span>
<span>F = 24 - 15 </span>
<span>F = 9 </span>
<span>i.e. the downstream speed of the water is 9 kph </span>
<span>Therefore, the boat's speed downstream is 15 + F = 15 + 9 = 24 kph.
the answer is: *24kph*</span>
Answer:
the rotational inertia of the cylinder = 4.85 kgm²
the mass moved 7.942 m/s
Explanation:
Formula for calculating Inertia can be expressed as:

For calculating the rotational inertia of the cylinder ; we have;




I ≅ 4.85 kgm²
mg - T ma and RT = I ∝
T = 


a = 4.1713 m/s²
Using the equation of motion

Answer:
It remains the same
Explanation:
It remains the same. This is because the number of protons doesn't change and the number of protons determines the atomic number.
Answer:
The minimum speed when she leave the ground is 6.10 m/s.
Explanation:
Given that,
Horizontal velocity = 1.4 m/s
Height = 1.8 m
We need to calculate the minimum speed must she leave the ground
Using conservation of energy



Put the value into the formula




Hence, The minimum speed when she leave the ground is 6.10 m/s.
Assuming Earth's gravity, the formula for the flight of the particle is:
<span>s(t) = -16t^2 + vt + s = -16t^2 + 144t + 160. </span>
<span>This has a maximum when t = -b/(2a) = -144/[2(-16)] = -144/(-32) = 9/2. </span>
<span>Therefore, the maximum height is s(9/2) = -16(9/2)^2 + 144(9/2) + 160 = 484 feet. </span>