You are correct, in that the velocity is zero, so its direction doesn’t mean anything, but just because the velocity is zero doesn’t mean the acceleration is zero. And it’s not zero, it’s -9.8m/s/s, as you acknowledge, so the direction of acceleration is meaningful.

Similarly, what is the acceleration of the ball at its highest point?

The ball reaches its highest point when its velocity is zero; the acceleration of gravity is never zero (it is always 9.8 m/s2 downward).

Can an object have a negative acceleration but still be speeding up?

When an object is speeding up, the acceleration is in the same direction as the velocity. Thus, this object has a positive acceleration. In Example B, the object is moving in the negative direction (i.e., has a negative velocity) and is slowing down.

## Is velocity zero at the highest point?

So, due to -ve acceleration along vertical direction velocity keep on decreasing and at the highest it becomes zero. As there is no acceleration acting along the horizontal direction so the final velocity is equal to the initial velocity at the highest point.

## Can the acceleration be zero?

If an object has zero acceleration, its velocity doesn’t have to be zero. Acceleration is a measure of the change in velocity over time. Zero acceleration means there is no change in velocity over time, namely constant velocity.

## Why is the velocity zero at maximum height?

The maximum height of the projectile is when the projectile reaches zero vertical velocity. From this point the vertical component of the velocity vector will point downwards. The horizontal displacement of the projectile is called the range of the projectile and depends on the initial velocity of the object.

## Can velocity and acceleration ever point in opposite directions?

If the velocity and acceleration are in the same direction (both have the same sign – both positive or both negative) the object is speeding up. If the velocity and acceleration are in opposite directions (they have opposite signs), the object is slowing down.

## What is the acceleration of a ball thrown up in the air?

If you throw the ball upward with a speed of 9.8 m/s, the velocity has a magnitude of 9.8 m/s in the upward direction. Now the ball is under the influence of gravity, which, on the surface of the Earth, causes all free-falling objects to undergo a vertical acceleration of –9.8 m/s2.

## What is the acceleration of the ball while it is at its maximum height?

No. And we know that the gravitational acceleration is approximately 9.8 m/s^2 and, as I said, it’s constant. So, at maximum height, and at any height, the acceleration of the ball is equal to the gravitational acceleration!

## Is it possible to have a changing speed and a constant velocity?

Speed is a magnitude of velocity, and so if the magnitude changes, then the velocity also has to change. But, the reverse case is possible: an object can have a constant speed but ever changing velocity. Speed 2. Direction if any of this or both alters velocity changes.

## What is the shape of a projectile?

If these two motions are combined – vertical free fall motion and constant horizontal motion – then the trajectory will be that of a parabola. An object which begins with an initial horizontal velocity and is acted upon only by the force of gravity will follow the path of the blue sphere.

## What happens to speed velocity acceleration when an object moves in a circle with uniform speed?

Circular Motion. When an object moves in a circle at a constant speed its velocity (which is a vector) is constantly changing. This constantly changing velocity means that the object is accelerating (centripetal acceleration).

## Is the initial velocity always zero?

When a body starts from rest or it changes it direction of motion,it is called as initial velocity.We generally consider initial velocity is equal to zero(u=0),only when the object starts from rest.Generally at time (t=0),the initial velocity is zero.

## Can the direction of the velocity of a body be changed when it’s acceleration is constant?

A object undergoing a constant acceleration has a constantly changing velocity. If the acceleration always points in the same direction as the velocity, the trajectory will be no different than if there were no acceleration, but in general acceleration will change the trajectory. Yes it can.

## Can an object with a constant acceleration reverse its direction of travel?

Sure. Although an object travelling in a circle is not a good example since it does not have constant acceleration (its acceleration vector is constantly changing direction.) The constant acceleration of gravity causes it to slow down, stop and reverse it’s direction.

## Can an object change direction while maintaining a constant acceleration?

(b) Can an object be accelerating when its speed is zero? (a) Yes, it is moving at a constant velocity. Can an object reverse its direction of travel while maintaining a constant acceleration? No, it can’t maintain a constant acceleration and change its direction.

## Can an object be moving with an acceleration of zero?

Yes, an object that was set in motion in the past by some force, but that is no longer being acted on by a net force, is moving but with zero acceleration, i.e. it is moving at constant velocity.

## What is an example of something that undergoes acceleration at a constant speed?

An example of an object accelerating but maintaining constant speed would be a car rounding a corner at constant speed. In such case the direction of motion, and hence the velocity, changes. If the velocity is constant, by assumption it does not change, thus there can be no acceleration in such case.

## What is the acceleration of an object in free fall at Earth’s surface?

As such, all objects free fall at the same rate regardless of their mass. Because the 9.8 N/kg gravitational field at Earth’s surface causes a 9.8 m/s/s acceleration of any object placed there, we often call this ratio the acceleration of gravity.

## How do speed velocity and acceleration relate to each other?

It is thus a vector quantity with dimension length/time². In SI units, acceleration is measured in meters/second². To accelerate an object is to change its velocity, which is accomplished by altering either its speed or direction (like in case of uniform circular motion) in relation to time.

## Is speed the acceleration?

Speed is the distance covered in a unit of time while acceleration is the rate of change of speed. The unit of speed in the metric system is meters per second (m/s) while that of acceleration is meters per second squared (m/s2). Speed is a scalar quantity while acceleration is a vector quantity.

## Is speed and acceleration the same thing?

When velocity is changing, the word acceleration is used. Acceleration is also a vector. You speed up if the acceleration and velocity point in the same direction. You slow down (also referred to as decelerating) if the acceleration and velocity point in opposite directions.

## What is the acceleration of the ball at its highest point?

The ball reaches its highest point when its velocity is zero; the acceleration of gravity is never zero (it is always 9.8 m/s2 downward).