Answer:
(a) Vf = 128 ft/s
(b) K.E = 122.8 Btu
Explanation:
(a)
In order to find the velocity of the object just before striking the surface of earth or the final velocity, we use 3rd equation of motion:
2gh = Vf² - Vi²
where,
g = 32.2 ft/s²
h = height = 253 ft
Vf = Final Velocity = ?
Vi = Initial Velocity = 10 ft/s
Therefore,
(2)(32.2 ft/s²)(253 ft) = Vf² - (10 ft/s)²
16293.2 ft²/s² + 100 ft²/s² = Vf²
Vf = √(16393.2 ft²/s²)
<u>Vf = 128 ft/s</u>
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(b)
The kinetic energy of the object before it hits the surface of earth is given by:
K.E = (0.5)(m)(Vf)²
where,
m = mass of object = 375 lb
K.E = Kinetic energy of object before it strikes the surface of earth = ?
Therefore,
K.E = (0.5)(375 lb)(128 ft/s)²
K.E = 3073725 lb.ft²/s²
Now, converting this to Btu:
K.E = (3073725 lb.ft²/s²)(1 Btu/25037 lb.ft²/s²)
<u>K.E = 122.8 Btu</u>
For the first hour, the slope is zero.
After that, the slope is -2 miles per hour.
Answer:
139.514 metres
Explanation:
Initial velocity of the truck = 6.6 m/s
Acceleration of the truck = 2.8 m/s^2
Time interval = 7.9 s
Therefore we use the formula,
s = ut + 1/2 at^2
*where s(the distance travelled)...u(the initial velocity)...t(the time period)
; s = 6.6(7.9) + 1/2 (2.8)(7.9)^2
; s = 52.14 + 87.374
The distance moved by the truck = 139.514m
Answer:
Yes
Explanation:
Newton's law of universal gravitation is usually stated that every particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses(m1 and m2) and inversely proportional to the square of the distance between their centers(r).
F = Gm1m2/r²
This is a general physical law derived from
empirical observations by what Isaac Newton called inductive reasoning.
when distance is doubled the gravitational force will be reduced by quarter not half.
