Answer:

**The net force is zero**

Explanation:

When an object is falling, there are two forces acting on it:

- The force of gravity, which is equal to the weight of the object, which pushes the object downwards

- The air resistance, which acts against the motion of the object, so it pulls upward

While the magnitude of the force of gravity is constant, the magnitude of the air resistance increases as the velocity of the falling object increases: at some point of the motion, the air resistance becomes equal in magnitude to the force of gravity. At this point, the net force on the object becomes zero, and according to Newton's second law, the acceleration of the object becomes also zero:

But zero acceleration means that the velocity of the object is now constant: this is known as terminal velocity.

The ceiling of a concert hall and conference halls are made curved so
that the sound that emanates from the source will reflect to any point of the
curve of these halls. Thereby, increasing the sound wave travelled across the
hall.

**Answer:**

0.9378

**Explanation:**

Weight (W) of the rider = 100 kg;

since 1 kg = 9.8067 N

100 kg will be = 980.67 N

W = 980.67 N

At the slope of 12%, the angle θ is calculated as:

The drag force D = Wsinθ

where;

A = 0.9 m²

V = 15 m/s

∴

Drag coefficient

**Answer:**

stars

those are stars in the galaxy

Answer:

D. 0.60 um

Explanation:

Given the following data;

Frequency = 5.0x10^14 Hz

Speed = 3 x 10^8 m/s

To find the wavelength;

Wavelength = speed/frequency

Substituting into the equation, we have

Wavelength = 3 x 10^8/5.0x10^14

Wavelength = 6 × 10^7m

But 1 meter (m) = 1000000 micrometer (um)

6 × 10^7 meter = 0.6 micrometer.