Answer:
True.
Explanation:
If the sum of the external forces on an object is zero, then the sum of the external torques on it must also be zero.
The net external force and the net external torque acting on the object have to be zero for an object to be in mechanical equilibrium.
Hence, the given statement is true.
Explanation:
rigidibiyu. jtibiti vekov oeo i irki jri kri oro lro
Answer:
dg= 942m
Explanation:
given the depth of the granite Us dg = 500m
time between the explosion t = 0.99s
the speed of sound in granite is Vg = 6000m/s
First of all calculate the time it takes the sound waves to travel down through the lake
Vw = dw/t1
t1 = dw/Vw
t1 = 500/1480
t1 = 0.338s.
Let dg be the depth of the granite basin, so the time it takes for the sound to travel down through the granite is t2 = dg/6000m/s......equation(1)
So the total time it takes to travel down to the oil surface will be
t1/2 = t1 + t2
t1/2= 0.338 + dg/6000.
since the reflection on the oil does not change the speed of sound, the sound will take travelling upto the surface the same time it takes to reach the oil
so; t = 2 t1/2
t1/2 = t/2 = 0.99s/2 = 0.495
Now insert into the values of t1/2 into the equation (1) and solve for dg;
we get 0.495 = 0.338 + dg/6000
dg = (0.495 - 0.338) x 6000
dg = 942m.
Answer:
What happens to the pressure of the air inside a sport ball when it is heated?
Explanation:
We can answer this question by thinking at what happen at microscopic level.
In fact, when the gas inside the ball is heated, the molecules of the gas start moving faster. As a result, the rate of collision of the molecules against the internal surface of the ball increases: and therefore, the pressure of the gas inside the ball increases.
We can also see this by looking at the ideal gas law, which states that:
where
p is the gas pressure
V is the gas volume
n is the number of moles
R is the gas constant
T is the absolute temperature of the gas
In this situation, the volume of the gas V is constant (since the ball has a constant volume), the number of moles n is also constant, as well as R. So we can rewrite this as
so we see that the pressure is directly proportional to the temperature: therefore, when the ball is heated, the pressure inside the ball increases.
On a speed/time graph, the height of the line at any point
shows the speed at that moment. If the line is horizontal,
then its height isn't changing, meaning that the speed isn't
changing. It's constant. The change is zero, until the line
starts rising or falling.
