1. A cube of metal has a mass of 0.402 kg and measures 3.37 cm on a side. Calcul
ID: 1300720 • Letter: 1
Question
1.A cube of metal has a mass of 0.402 kg and measures 3.37 cm on a side. Calculate the density and identify the metal.
2.A 73-kg person sits on a 3.7-kg chair. Each leg of the chair makes contact with the floor in a circle that is 1.4 cm in diameter. Find the pressure exerted on the floor by each leg of the chair, assuming the weight is evenly distributed.
3.A certain dam is holding back fresh water 181 m deep. What is the water pressure at the base of the dam?
4.A raft is 4.7 m wide and 6.5 m long. When a horse is loaded onto the raft, it sinks 2.7 cm deeper into the water. What is the weight of the horse?
5.A solid block is suspended from a spring scale. The reading on the scale when the block is completely immersed in water is 24.1 N, and the reading when it is completely immersed in a liquid of density 850 kg/m3is 25 N.
(a) What is the block's volume?
(b) What is the block's density?
6.During a thunderstorm, winds with a speed of 48.2 m/s blow across a flat roof with an area of 756 m2.
(a) Find the magnitude of the force exerted on the roof as a result of this wind.
(b) Is the force exerted on the roof in the upward or downward direction?
7.The world's longest suspension bridge is the Akashi Kaikyo Bridge in Japan. The birdge is 3710 m long and is constructed of steel. How much longer is the bridge on a warm summer day (27.0
Explanation / Answer
1)density = mass/volume
=0.402 kg/(0.337m)^3 =1.35*10^4 kg/m^3
3) I had to convert to feet. 181 meters to feet is 593.832021 feet.
There are 2.31 pounds of pressure per foot. 593.832021/2.31= 257.07psi.
If you need it in kpa, it is 1772.43 kpa. I cant help you exactly with that equation though.
4)weight of horse = weight of displaced water
water_mass_density = 1 g / cm^3 = 1000 kg / m^3
weight horse = density * g * volume_displaced
weight horse = 1000 * 9.81* (4.7*6.5*0.027 )
weight horse = .............. N
5)This is a "two equations, two unknowns" problem.
You need to construct a force balance equation for the three forces (gravity, buoyancy, and spring scale tension) in both scenarios, and then solve for the two unknowns.
In any of the scenarios, we write the force balance as:
W = T + B
Where W is the object's true weight, T is the tension in the spring scale, and B is the buoyancy force from the fluid.
We of course know that:
W = m*g
The situations will change what T and B are, but since it is the same object, m*g remains unchanged.
Thus, we construct two versions as:
m*g = T1 + B1
m*g = T2 + B2
In terms of the density of the fluids and the volume of the object (which will not change from case to case), we express buoyancy as:
B1 = rho1*g*V
B2 = rho2*g*V
Thus:
m*g = T1 + rho1*g*V
m*g = T2 + rho2*g*V
Now all you need to do is do some algebra, and solve for m and V.
Eventually, you will derive:
m = (rho1*T2 - rho2*T1)/(g*(rho1 - rho2))
V = (T2 - T1)/(g*(rho1 - rho2))
Let's make fluid 1 be water, and fluid 2 be the sparser liquid.
Data:
T1 = 24.1 N
T2 = 25N
rho1 = 1000 kg/m^3
rho2 = 850 kg/m^3
g = 9.8 N/kg
This will calculate:
m=.......kg
V=......... m^3
6)A. v1 (upper surface) = 48.2 m/s
v2 (lower surface) = 0 m/s
Lift = area*density*(v1^2-v2^2)/2 = ......... N
B. Upward; pressure decreases as velocity increases
7)
We know Q = 0 in Joules apparatus (insulated)
?Eint = Q + W; ?Eint = W
Work = 2 blocks (mgh)
Work = 2(0.85*9.8*0.4) 5= ........J
?T = workJ (1.0 C
We know Q = 0 in Joules apparatus (insulated)
?Eint = Q + W; ?Eint = W
Work = 2 blocks (mgh)
Work = 2(0.85*9.8*0.4) 5= ........J
?T = workJ (1.0 C
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.