At the train station, you notice a large horizontal spring at the end of the track where the train comes in. This is a safety de
1 answer:
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Answer: It takes 2.85 seconds.
Explanation: according to the question, the kinematics equation for vertical motion is
y₀ is the initial postion and equals 0 because it is fired at ground level;
v₀ is the initial speed and eqauls 14m/s;
g is gravity and it is 9.8m/s²;
y(t) is the final position and equals 0 because it is when the pumpkin hits the ground;
Rewriting the equation, we have:
0 + 14t - = 0
14t - 4.9t² = 0
t(14 - 4.9t) = 0
For this equation to be zero,
t = 0 or
14 - 4.9t = 0
- 4.9t = - 14
t =
t = 2.86
It takes 2.86 seconds for the pumpkin to hit the ground.
Force of 500 N is acting on the parachutist.
Parachutist applies 500 N force in downward direction.
Answer:
300 N upward
Solution:
Parachutist feels air resistance of 800 N.
Thus, 800 N of force is acting in upward direction.
Total force acting on the parachutist is given by,
= air resistance force - force of parachutist
= 800-500
= 300 N
Direction of force is in upward direction because the air resistance force is more than force of parachutist.
<h2>Answer: the falling time</h2>
Explanation:
When a body or object falls, basically two forces act on it:
1. The force of air friction, also called<em> </em><u><em>"drag force"</em></u> :
(1)
Where:
is the drag coefficient
is the density of the fluid (air for example)
is the velocity
is the transversal area of the object
So, this force is proportional to the transversal area of the falling element and to the square of the velocity.
2. Its <u>weight </u>due to the gravity force :
(2)
Where:
is the mass of the object
is the acceleration due gravity
So, at the moment <u>when the drag force equals the gravity force, the object will have its terminal velocity:</u>
(3)
(4)
(5) This is the terminal velocity
As we can see, there is no "falling time" in this equation.
Therefore, the terminal velocity is not dependent on the falling time.