Answer:
20 m/s
Explanation:
Given:
Δy = 0.02 km = 20 m
v₀ = 0 m/s
a = 9.8 m/s²
Find: v
v² = v₀² + 2aΔy
v² = (0 m/s)² + 2 (9.8 m/s²) (20 m)
v = 19.8 m/s
Rounded to one significant figure, the final velocity is 20 m/s towards the ground.
Answer:
It is called force of friction
Explanation:
The force of friction is a force that acts between two objects whose surfaces are in contact with each other.
Consider the typical case of an object sliding along a certain surface. There are two types of frictions:
- Static friction: this is the force of friction that acts when the object is not in motion yet. If you push the object forward with a force F, the object will not move immediately, but it will "oppose" to this motion with a force of static friction exactly equal to the push applied:
However, this force of static friction has a maximum value, which is given by
where
is the coefficient of static friction
N is the normal reaction exerted by the surface on the object
So, when becomes greater than , the static friction is no longer able to balance the push applied, and the object will start sliding forward.
- Kinetic friction: this is the force of friction that acts when the object is already in motion. Its magnitude is given by
where
is the coefficient of kinetic friction, and its value is generally smaller than . The direction of this force is also opposite to the direction of motion of the object.
Answer:
Explanation:
(a) The velocity of object is zero when it is at maximum height.
(b) The direction of velocity changes as it starts moving downwards after it reaches the maximum height.
(c) Acceleration due to gravity always acts downwards so its sign remains same.
Answer:
The correct answer is d. tension pneumothorax.
Explanation:
The increasing build-up of air that is in the pleural space is what we call the tension pneumothorax and this happens due to the lung laceration that lets the air to flee inside the pleural space but it does not return.
The answer would be a positive charge