Forces affect how objects move. They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity. Remember that acceleration is a change in velocity.
Speeding the object up, slowing the object down, or changing the direction it is moving in would all qualify for changing the object’s velocity.
Newton’s second law says that when a constant force acts on a massive body, it causes it to accelerate, i.e., to change its velocity, at a constant rate. In the simplest case, a force applied to an object at rest causes it to accelerate in the direction of the force.
The factors affecting the terminal velocity of an object include: its mass. its surface area. the acceleration due to gravity, g.
Speed, being a scalar quantity, is the rate at which an object covers distance. The average speed is the distance (a scalar quantity) per time ratio. Velocity is the rate at which the position changes. The average velocity is the displacement or position change (a vector quantity) per time ratio.
Acceleration is the rate of change of velocity with time. Any change in the velocity of an object results in an acceleration: increasing speed (what people usually mean when they say acceleration), decreasing speed (also called deceleration or retardation ), or changing direction ( called centripetal acceleration ).
Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object’s movement. Put another way, speed is a scalar value, while velocity is a vector.
Both velocity and acceleration are vector quantities, meaning that they use both magnitudes and a specified direction. velocity – the rate of displacement of a moving object over time. acceleration – the rate of velocity change over time.
In physics, the three types of acceleration are changes in speed, direction and both simultaneously. The word “velocity” is often used in place of speed.
There is an increase in the resistance to motion since now there is a component of the weight acting parallel to the direction of motion of the car. This causes an initial net force downwards which causes a deceleration. The forces balance out once again when the resistive forces decreases to a certain value.
Can A Body Have A Constant Velocity And Still Have A Varying Speed? No, a body can not have its velocity constant, while its speed varies.
Chapter 19 – Motion
|What two factors determine speed?||distance & time|
|What is the difference between speed and velocity?||Velocity has direction speed does not.|
|What best represents acceleration as presented on a graph?||velocity change vs. time|
|What is force?||a push or pull acting on an object.|
The average velocity only depends on the starting and ending point, not the path but the speed depends on the path (in this definition). Also with this definition, the average speed is a scalar quantity and not a vector quantity. Oh, most of the textbooks used this definition of average speed.
Mass does not affect the speed of falling objects, assuming there is only gravity acting on it. Both bullets will strike the ground at the same time. The horizontal force applied does not affect the downward motion of the bullets — only gravity and friction (air resistance), which is the same for both bullets.