Answer:
. Doppler ultrasound is based on absorption of sound, and other
ultrasound technology is based on reflection.D.
Explanation:
Answer:
When like charges come together, they repel each other. For instance, when the north and south poles of a magnet come together, they push each other apart. The like poles in the magnet repel each other and unlike poles attract each other much. The same reaction occurs in like and unlike charges. Also, the repulsion acts along the line between the two charges.
<span>We can use an equation to find the gravitational force exerted on the HST.
F = GMm / r^2
G is the gravitational constant
M is the mass of the Earth
m is the mass of the HST
r is the distance to the center of the Earth
This force F provides the centripetal force for the HST to move in a circle. The equation we use for circular motion is:
F = mv^2 / r
m is the mass of the HST
v is the tangential speed
r is the distance to the center of the Earth
Now we can equate these two equations to find v.
mv^2 / r = GMm / r^2
v^2 = GM / r
v = sqrt{GM / r }
v = sqrt{(6.67 x 10^{-11})(5.97 x 10^{24}) / 6,949,000 m}
v = 7570 m/s which is equal to 7.570 km/s
HST's tangential speed is 7570 m/s or 7.570 km/s</span>
Answer:
It is a example of physical change
Answer:
0.64 J/g°C
Explanation:
Using the formula;
Q = m × c × ∆T
Where;
Q = amount of heat
m = mass (g)
c = specific heat capacity
∆T = change in temperature (°C)
In this case:
Q (water) = - Q (metal)
mc∆T (water) = - mc∆T (metal)
According to the information in this question,
For water; m = 100g, c = 4.18J/g°C, ∆T = (25°C - 20°C)
For metal; m = 50g, c =?, ∆T = (25°C - 90°C)
mc∆T (water) = - mc∆T (metal)
100 × 4.18 × (25°C - 20°C) = - {50 × c × (25°C - 90°C)}
100 × 4.18 × 5 = - {50 × c × -65}
2090 = -{-3250c}
2090 = 3250c
c = 2090/3250
c = 0.643
c = 0.64J/g°C
