Answer:
m = 4.5021 kg
Explanation:
given,
Apparent mass of aluminium = 4.5 kg
density of air = 1.29 kg/m³
density of aluminium = 2.7 x 10⁷ kg/m³
true mass of the aluminium = ?
Weight in Vacuum
W = m g
W = ρV g
Air buoyancy acting on aluminium
B = ρ₀V g
Volume is the same in both cases since the volume of the aluminum
displaces an equal amount of volume air.
Apparent weight:
ρV g − ρ₀V g = 4.5 g
ρV − ρ₀V = 4.5

m = ρV


m = 4.5021 kg
Hertz is a measurement of the frequency that a wave is occurring.
Answer:
a) 2.5m/s
b) 0.91m/s
c) 0m/s
Explanation:
Average velocity can be said to be the ratio of the displacement with respect to time.
Average speed on the other hand is the ratio of distance in relation to time
Thus, to get the average velocity for the first half of the swim
V(average) = displacement of first trip/time taken on the trip
V(average) = 50/20
V(average) = 2.5m/s
Average velocity for the second half of the swim will be calculated in like manner, thus,
V(average) = 50/55
V(average) = 0.91m/s
Average velocity for the round trip will then be
V(average) = 0/75, [50+25]
V(average) = 0m/s
Answer:

Explanation:
<u>Free Fall Motion</u>
A free-falling object refers to an object that is falling under the sole influence of gravity. If the object is dropped from a certain height h, it moves downwards until it reaches ground level.
The speed vf of the object when a time t has passed is given by:

Where 
Similarly, the distance y the object has traveled is calculated as follows:

If we know the height h from which the object was dropped, we can solve the above equation for t:

The stadium is h=32 m high. A pair of glasses is dropped from the top and reaches the ground at a time:

The pen is dropped 2 seconds after the glasses. When the glasses hit the ground, the pen has been falling for:

Therefore, it has traveled down a distance:

Thus, the height of the pen is:
