Answer:
A line crossing the x-axis in a velocity-time graph means that the moving object has changed its direction.
Explanation:
Velocity-Time graph:
A velocity-time graph is a two dimensional graph with velocity at its y-axis and time at its x-axis. At any point, value of y represents the velocity and value of x represents the time. The slope of the graph gives us the acceleration or deceleration of the moving object.
In a velocity-time graph:
- A straight line represents constant velocity.
- A diagonal line means that the velocity of a body is changing.
*Referring to the figure attached with the answer*
The velocity of the moving object increases at a constant rate for the first 10 minutes. Then the velocity is 60 m/min for the next 5 minutes. After that the velocity is decreasing. Till 30th minute when the velocity is at 0 m/min.
What happens here?
Velocity is a vector quantity. It has some direction. In a velocity-time graph, we are only concerned with two directions of velocity:
- Forward direction
- Backward direction
So, the object stops at 30th minute and starts moving in the reverse direction after that with an increasing velocity. <u>The point where the line cuts the x-axis is basically the point where the object starts moving in the reverse direction.</u>
I need to force in order to answer. What is it
Answer:
Explanation:
Given;
The operational pressure of the cooker, 
area of the opening, 
- We know that the gauge pressure is measured with respect to the atmospheric pressure. As the atmospheric pressure acts on all the components of the system being observed so, we only need to counter the gauge pressure.
As the petcock sits on the opening of the cross-section so, it balances the built-in pressure due to its weight.
<u>Hence:</u>
where:
mass of the petcock
acceleration due to gravity
I don't like any of those choices. But if you absolutely have to pick your answer
from this list, then it has to be 'D'.
The ocean is an enormous storage vessel for heat. It gets heat from the air in
the Summer ... which somewhat cools places near the coast ... and it releases
heat into the air during the Winter ... which warms places near the coast.
So I guess it's true that ocean surfaces change temperature more slowly than
land surfaces do, and they influence the land nearby in the process. But this
ignores the reason for the slow changes in ocean surface temperature. It's a
lot like saying that the loud noise produced by a race car is the result of the
car's ability to appear in a far different location after a short time.
Answer:
Explanation:
As we know that the acceleration due to gravity decreases with height.
At certain height it will get to the half of its value on the surface of the earth.
As we know that the weight on the surface of the earth is given as:
where:
m = mass of the object
g = acceleration due to gravity of the substance
Since mass of the substance is constant so the variation is weight is possible only due to change in the acceleration due to gravity.
<u>We know that the variation of the acceleration due gravity with height is given as:</u>
where:
value to acceleration due to gravity at height h
g = acceleration due to gravity at the earth's surface
h = height of the object
R = radius of the earth = 
according to question the weight becomes half, so,:
is the height a rocket has to go above Earth's surface before its weight is half of what it is on Earth.
