Answer:
1. 5 m/s
2. 8 m/s
3. 10 s
4. 3 m/s
Explanation:
1. Average speed = distance / time
s = 20 m / 4 s
s = 5 m/s
2. First, find the time to travel from A to B:
60 m = 10 m/s × t
t = 6 s
Now find the average speed from A to C:
s = 80 m / (6 s + 4 s)
s = 8 m/s
3. If t is the time traveling from C back to B, and the average speed of the whole trip is 5 m/s, then:
5 m/s = 100 m / (6 s + 4 s + t)
t = 10 s
4. Average velocity = displacement / time
v = 60 m / 20 s
v = 3 m/s
Answer:
The surface tension of the water is 6.278×10⁻² N/m
error = 13.65%
Explanation:
The surface tension of water is given by

Where F is the force acting on water and L is the length over which is force is acted.
We are given the mass of 100 droplets of water
M = 3.78 g
n = 100
The mass of 1 droplet is given by

The force acting on a single droplet of water is given by

Where m is the mass of water droplet and g is the acceleration due to gravity


The circumferential length of the droplet is given by

Where d is the diameter

Now we can find out the required surface tension of the water

Therefore, the surface tension of the water is 6.278×10⁻² N/m
The tabulated value of the surface tension of water at 20 °C is given by

The percentage error between tabulated and calculated surface tension is given by



Answer:
the time taken for the ball to hit the ground is 0.424 s
Explanation:
Given;
velocity of the ball, u = 5 m/s
height of the house which the ball was kicked, h = 3m
Apply kinematic equation;
h = ut + ¹/₂gt²
where;
h is height above ground
u is velocity
g is acceleration due to gravity
t is the time taken for the ball to hit the ground
Substitute the given values and solve for t
3 = 5t + ¹/₂(9.8)t²
3 = 5t + 4.9t²
4.9t² + 5t -3 = 0
a = 4.9, b = 5, c = -3
Solve for t using formula method

the answer is D) The air in the aquarium is saturated
none of the other answers were realistic AND I took this before so I know the right answer.
<h3>yes, there are human health risks caused by exposure to x rays</h3>
- describe the main risk (s) ::: - may cause damage to cells in the body
- large doses may lead cells to be cancerous
- causes mutations in the DNA
- describe common sources of exposure ( or overexposure ) :::
- natural background radiation e.g. - cosmic rays
- medical radiation e.g. - CT scans & medical x - rays
- man - made radiation e.g. - airport security scanners
- describe a technology, device, or behavior that can be used for protection, or to decrease exposure :::
- x - ray beam filters
- digital x - ray detectors
- technologies reduce radiation doses in radiography &
mammography
<em>hope that helps !!</em>