A motor boat is moving 10 km/h relative to the water. If the boat travels in a river that flows at 10km/h, what is the velocity relative to the shore when it heads directly up stream?
A book on your desk will sit there and not move, unless you apply a force to the book to move it. If your arm pushed the book, that would be a force.
If you drive in a car and hit a wall without the force of a seat belt to stop you, your body will continue to move even though the car has stopped. This is why people go through the windshield.
“An object moving at a constant velocity will keep moving at that velocity unless a net force acts on it. If an object is at rest it will stay at rest unless a net force acts on it.”
An object in motion will stay in motion (rest at rest)
The measure of the force of gravity on an object is weight.
Weight is different from mass!!!
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Mass vs. Weight Scale Balance Measuring Tool Changed by location Newton (N) Amount of gravitational force acting on an object Weight Not changed by location g, kg The amount of matter in an object Mass Location Unit Definition
Because any force can be calculated using the equation F = m x a , weight of an object (a force) can be calculated using a similar equation W = m x a .
Because weight is the force of gravity on an object the rate of acceleration is the pull of gravity. (remember? 9.8 m/s 2 )
A projectile’s horizontal and vertical motion are completely independent of each other.
Gravity will effect a projectile and a falling object in the same way.
Therefore, if an object is dropped and thrown at the same time they will hit the ground at the same time. It does not matter that the projectile travels a farther distance.
Acceleration is a rate of change in velocity caused by a change in speed or direction!
If you are riding a bicycle in a straight path you will not accelerate. But, if you travel around a curve the speed will accelerate because the direction is changing.
When a car goes around a sharp curve the centripetal force is the friction between the tires and the road.
Although, if the road is icy, the tires may lose their grip. The amount of centripetal force will not be enough to overcome the car’s inertia.
So the car would continue to move in a straight line.
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As the moon orbits the Earth, the force of gravity acting upon the moon provides the centripetal force required for circular motion. As a bucket of water is tied to a string and spun in a circle, the force of tension acting upon the bucket provides the centripetal force required for circular motion. As a car makes a turn, the force of friction acting upon the turned wheels of the car provide the centripetal force required for circular motion.
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Without a centripetal force, an object in motion continues along a straight-line path. With a centripetal force, an object in motion will be accelerated and change its direction.
For every action, there is an equal and opposite reaction.
For example: If you jump out of a boat the boat exerts a force on your feet pushing your forward, although your feet exert an equal and opposite force on the boat sending it backwards.
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