4. Table 2.4 shows how the displacement of a runner changed
during a sprint race. Draw a displacement–time graph to show
this data, and use it to deduce the runner’s speed in the middle
of the race.
Table 2.4 Data for a sprinter during a race
Displacement
(m)
0 4 10 20 50 80 105
Time (s) 1 2 3 6 9 12
Answer:
The distance between knothole and the paint ball is 0.483 m.
Explanation:
Given that,
Height = 4.0 m
Distance = 15 m
Speed = 50 m/s
The angle at which the forester aims his gun are,




Using the equation of motion of the trajectory
The horizontal displacement of the paint ball is


Using the equation of motion of the trajectory
The vertical displacement of the paint ball is



Put the value into the formula


We need to calculate the distance between knothole and the paint ball



Hence, The distance between knothole and the paint ball is 0.483 m.
A bathroom scales works due to gravity. Under normal
conditions, a reading can be obtained when your body is pushing some force on
the scale. However in this case, since you and the scale are both moving
downwards, so your body is no longer pushing on the scale. Therefore the answer
is:
<span>The reading will drop to 0 instantly</span>
Answer:
The friend on moon will be richer.
Explanation:
We must calculate the mass of gold won by each person, to tell who is richer. For that purpose we will use the following formula:
W = mg
m = W/g
where,
m = mass of gold
W = weight of gold
g = acceleration due to gravity on that planet
<u>FOR FRIEND ON MOON</u>:
W = 1 N
g = 1.625 m/s²
Therefore,
m = (1 N)/(1.625 m/s²)
m(moon) = 0.6 kg
<u>FOR ME ON EARTH</u>:
W = 1 N
g = 9.8 m/s²
Therefore,
m = (1 N)/(9.8 m/s²)
m(earth) = 0.1 kg
Since, the mass of gold on moon is greater than the mass of moon on earth.
<u>Therefore, the friend on moon will be richer.</u>