True or false: while riding a bicycle up a gentle hill, it fairly easy to increase your potential energy, but to increase your kinetic energy would ...
Answer:
1. Force = mass x acceleration - Newton
2. A planet moves faster in the part of its orbit nearer the Sun and slower when farther from the Sun, sweeping out equal areas in equal times - Kepler
3. For any force, there is an equal and opposite reaction force - Newton
.
4. An object moves at constant velocity if there is no net force acting upon it - Newton
5. The orbit of each planet about the Sun is an ellipse with the Sun at one focus - Kepler.
6. More distant planets orbit the Sun at slower average speeds, obeying the precise mathematical relationship p2-a3 - Kepler.
Explanation:
The three laws of planetary motion formulated by Johannes Kepler or Kepler's laws of planetary motion:
- The first law states that the planets move around the Sun in an elliptical orbit with the Sun at one of the foci.
- The second law states that the line segment joining a planet to the Sun sweeps out equal areas in equal time.
- The third law states that the square of the orbital period (p) of a planet is directly proportional to the cube of the mean distance (a) from the Sun (or semi-major axis of its orbit) i.e., p² is proportional to a³.
The three laws of motion formulated by Sir Isaac Newton or Newton's laws of motion:
- The first law, also known as the law of inertia states that an object at rest or moves at a constant velocity will remain at rest or keep moving at a constant velocity unless it is acted upon by a force.
- The second law states that the total force (F) applied on an object is directly related to the acceleration (a) of that object produced by the applied force and the mass (m) of the object, i.e., F = ma (assuming the mass m is constant).
- The third law, also known as the law of action and reaction states that when an object exerts a force on another object, then the latter exerts a force equal in magnitude and opposite in direction on the former object i.e., for every action, there is an equal and opposite reaction. The example includes the recoiling of a gun when it fires a bullet forward.
Answer:
Explanation:
Kinematics equation for constant acceleration:
Answer:
0.405 seconds
Explanation:
Consider the amount of time it takes the block to fall from 53 m up to 14 m above the ground; then consider the amount of time it takes the block to fall from 53 m up to 2 m above the ground.
First, d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 × 39 / 9.8)^1/2 = 2.8212 seconds
Then, to fall from 53 down to 2 meters...
d = (1/2) gt^2 or t= ( 2 d / g)^1/2
= ( 2 * 51/ 9.8 )^1/2 = 3.2262 seconds
So the amount of time it takes for the block to fall from 14 m upto 2 m above the ground
3.2262 - 2.8212 = 0.405 seconds
this is how much time there is from when the man sees the block until it hits him. Not much time...
