Before you even look at the questions, look over the graph, so you know what kind of information is there.
The x-axis is "time". OK. You know that as the graph moves from left to right, it shows what's happening as time goes on.
The y-axis is "speed" of something. OK. When the graph is high, the thing is moving fast. When the graph is low, the thing is moving slow. When the graph slopes up, the thing is gaining speed. When the graph slopes down, the thing is slowing down. When the graph is flat, the speed isn't changing, so the thing is moving at a constant speed.
NOW you can look at the questions.
OMG ! It's only ONE question: What's happening from 'c' to 'd' ? Well I don't know. Perhaps we can figure it out if we LOOK AT THE GRAPH !
-- Between c and d, the graph is flat. The speed is not changing. It's the same speed at d as it was back at c .
What speed is it ?
-- Look back at the y-axis. The speed at the height of c and d is 'zero' .
-- The 2nd and 4th choices are both correct. From c to d, <em>the speed is constant</em>. The constant speed is zero. <em>The car is not moving</em>.
Answer:
a-1 Graph is attached. The relation is linear.
a-2 The corresponding height for 68 kPa Pressure is 7.54 m
a-3 The corresponding weight for 68 kPa Pressure is 1394726kg
b The original height of the column is 5.98 m
Explanation:
Part a
a-1
The graph is attached with the solution. The relation is linear as indicated by the line.
a-2
By the equation

Here
- P is the pressure which is given as 68 kPa.
- ρ is the density of the oil whose SG is 0.92. It is calculated as

- g is the gravitational constant whose value is 9.8 m/s^2
- h is the height which is to be calculated

So the height of column is 7.54m
a-3
By the relation of volume and density

Here
- ρ is the density of the oil which is 920 kg/m^3
- V is the volume of cylinder with diameter 16m calculated as follows

Mass is given as

So the mass of oil leading to 68kPa is 1394726kg
Part b
Pressure variation is given as

Now corrected pressure is as

Finding the value of height for this corrected pressure as

The original height of column is 5.98m
Answer:
A chair at rest on the floor has two forces acting on it its own weight that pulls it downward and the floor pushing upward on the chair, both of these forces are acting on it but the net force is 0, so the chair remains at rest and its velocity stays at 0.
Answer:
5.3 m/s
Explanation:
First, find the time it takes for him to fall 7m.
y = y₀ + v₀ t + ½ at²
0 = 7 + (0) t + ½ (-9.8) t²
0 = 7 − 4.9 t²
t ≈ 1.20 s
Now find the velocity he needs to travel 6.3m in that time.
x = x₀ + v₀ t + ½ at²
6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²
v₀ ≈ 5.27 m/s
Rounded to two significant figures, the man must run with a speed of 5.3 m/s.
Answer:
The students conclusion is wrong.
Explanation:
The students conclusion is wrong because liquids can not soak into concrete. The water evaporated because it was a hot sunny day. The water turned into a gas called water vapor.