Objects should be cooled before their mass is determined on a sensitive balance because it could damage the balance. Also, because it would give you wrong reading of the mass. Hot objects would warm the air around it. A warm air would expand and would produce convection as it rises causing to give the object a mass that is less than the actual. Another reason would be it would cause instability in the readings, the mass would fluctuate every now and then due to the convection currents around the object. It is always recommended to weigh the masses of objects that are in room temperature.
Answer:
Explanation:
= Velocity of one lump = 
= Velocity of the other lump = 
m = Mass of each lump = 
The collision is perfectly inelastic as the lumps stick to each other so we have the relation
The velocity of the stuck-together lump just after the collision is .
Answer:
39.7 m
Explanation:
First, we conside only the last second of fall of the body. We can apply the following suvat equation:
where, taking downward as positive direction:
s = 23 m is the displacement of the body
t = 1 s is the time interval considered
is the acceleration
u is the velocity of the body at the beginning of that second
Solving for u, we find:
Now we can call this velocity that we found v,
v = 18 m/s
And we can now consider the first part of the fall, where we can apply the following suvat equation:
where
v = 18 m/s
u = 0 (the body falls from rest)
s' is the displacement of the body before the last second
Solving for s',
Therefore, the total heigth of the building is the sum of s and s':
h = s + s' = 23 m + 16.7 m = 39.7 m
Answer:
A) B = 24 ft
B) H = 24.08 ft
C) M.A = 12.04
D) P = 13.7 lb
Explanation:
A)
Minimum allowable length of base of ramp can be found as follows:
Slope = H/B
where,
Slope = 1/12
H = Height of Ramp = 2 ft
B = Length of Base of Ramp = ?
Therefore,
1/12 = 2 ft/B
B = 2 ft * 12
<u>B = 24 ft</u>
B)
The length of the slope of ramp can be found by using pythagora's theorem:
L = √H² + B²
where,
H = Perpendicular = height = 2 ft
B = Base = Length of Base of Ramp = 24 ft
L = Hypotenuse = Length of Slope of Ramp = ?
Therefore,
H = √[(2 ft)² + (24 ft)²]
<u>H = 24.08 ft</u>
D)
The mechanical advantage of an inclined plane is given by the following formula:
M.A = L/H
M.A = 24.08 ft/2 ft
<u>M.A = 12.04</u>
D)
Another general formula for Mechanical Advantage is:
M.A = W/P
where,
W = Ideal Load = 165 lb
P = Ideal Effort Force = ?
Therefore,
12.04 = 165 lb/P
P = 165 lb/12.04
<u>P = 13.7 lb</u>
