Answer:
1) 9.8×10⁻⁹ m/s
2) 50970.3238656 L
Explanation:
1) In 30 days hair grows 1 inch
1 inch = 2.54 cm
1 cm = 0.01 m
2.54 cm = 2.54 × 0.01 m
⇒2.54 cm = 0.0254 m
30 days = 30×24×60×60 = 2592000 seconds
Speed = Distance / Time
Speed at which hair grows is 9.8×10⁻⁹ m/s
2) 1 ft = 0.3048 m
0.3048 m = 30.48 cm
1 ft = 30.48 cm
15 ft = 15×30.48 = 457.2 cm
8 ft = 8×30.48 = 243.84 cm
Volume of water in pool = Length × Width × Depth
⇒Volume of water in pool = 457.2×457.2×243.84
⇒Volume of water in pool = 50970323.8656 cm³
or
Volume of water in pool = 15×15×8 = 1800 ft³
1 ft³ = 30.48³ cm³
1800 ft³ = 30.48³ × 1800 = 50970323.8656 cm³
Converting to liters
1 L = 1000 cm³
0.001 L = 1 cm³
50970323.8656 cm³ = 50970323.8656×0.001 = 50970.3238656 L
Volume of water in pool is 50970.3238656 L
Answer:
Explanation:
ignoring air resistance, the kinetic energy at water impact will equal the potential energy converted
½mv² = mgh
v = √(2gh)
v = √(2(9.81)2.1) = 6.4188... m/s
after impact, an impulse will result in a change of momentum.
There is a downward impulse due to gravity equal to the weight of the stone and an upward average force due to water resistance and buoyancy force.
FΔt = mΔv
(F - mg)Δt = m(vf - vi)
(F - mg) = m(vf - vi)/Δt
F = m(vf - vi)/Δt + mg
F = m((vf - vi)/Δt + g)
F = 1.05(((½(-6.4188) - -6.4188)/ 1.83) + 9.81)
F = 12.14198...
F = 12.1 N
Construct a vector diagram. It will be a right-angled triangle. One vector (the hypotenuse) represents the heading of the boat, one represents the current and one represents the resultant speed of the boat, which I'll call x. Their magnitudes are 20, 3 and x. Let the required angle = theta. We have:
<span>theta = arcsin(3/20) = approx. 8.63° </span>
<span>The boat should head against the current in a direction approx. 8.63° to the line connecting the dock with the point opposite, or approx. 81.37° to the shore line. </span>
<span>x = sqrt(20^2 - 3^2) </span>
<span>= sqrt(400 - 9) </span>
<span>= sqrt 391 </span>
<span>The boat's crossing time = </span>
<span>0.5 km/(sqrt 391 km/hr) </span>
<span>= (0.5/sqrt 391) hr </span>
<span>= approx. 0.025 hr </span>
<span>= approx. 91 seconds</span>
Explanation:
According to Newton's First Law of motion, if a box is pushed with no external resistance, the box will keep on moving due to the absence of external force. It might gets stopped due to frictional force that is acting between the surface and the ball. The first law of motion is also known as law of inertia. the magnitude of force acting on the object is given by second law of motion.
