Answer:
The acceleration of the sprinter is 1.4 m/s²
Explanation:
Hi there!
The equation of position of the sprinter is the following:
x = x0 + v0 · t + 1/2 · a · t²
Where:
x = position of the sprinter at a time t.
x0 = initial position.
v0 = initial velocity.
t = time.
a = acceleration.
Since the origin of the frame of reference is located at the starting point and the sprinter starts from rest, then, x0 and v0 are equal to zero:
x = 1/2 · a · t²
At t = 9.9 s, x = 71 m
71 m = 1/2 · a · (9.9 s)²
2 · 71 m / (9.9 s)² = a
a = 1.4 m/s²
The acceleration of the sprinter is 1.4 m/s²
Answer:
See the answers below
Explanation:
This problem can be solved by means of the law of conservation of energy, which tells us that the energy between two points is conserved, that is, remains the same.
That is to say, we have two points, the point A where it starts to move and reaches the point B that is 1.5 [m] high, where it stops.
The key to solving this problem is to identify the types of energies at each point. At point A we have kinetic energy and potential energy where the block moves at speed 3 [m/s] at a height of 4 [m]. Whereas at Point B we only have potential energy, since the body is at a height of 1.5 [m], relative to the ground.
a)
Since between the displacement between points A and B there is a friction force, this friction force decreases the final energy in B, in this way the energy or work of the friction will have a negative sign.
Now replacing in the above equation.
b)
We must use the same equation, but this time eliminating the Working term due to friction.
As we can see without friction the block can reach a higher height
Answer:
This is something for biology, it shouldnt be in the physics subject
Explanation:
Answer:A force can be described as a push or a pull. Pushes and pulls can be seen to act on objects when they begin to move, speed up, slow down or change direction.
The image gallery on this page shows children at play using push and pull actions to move objects. Children use push and pull all the time while at play. While playing, students learn to manipulate objects and materials and make observations about their actions.
Teachers may use this teaching resource over a number of lessons to explore and develop their students' understanding that a push or a pull affects how an object moves or changes shape.
Explanation:
Power = (work done) / (time to do the work)
= (21,000 Joules) / (30 seconds)
= (21,000 / 30) joule/sec
= 700 watts