A car is travelling on a highway
Can it have a negative velocity & a positive acceleration at the same time?
Can the car change d direction of its velocity when travelling with constant acceleration?
negative velocity depends on which way + displacement is. The answer is yes, think on it.
Yes if acceleration is perpendicular to velocity. You can also do it if you carefully define the coordinate system, especially in cylindrical coordinates.
To answer your first question, let's start by understanding what velocity and acceleration mean.
Velocity is a vector quantity that describes the rate at which an object changes its position. It includes both speed (the magnitude of the velocity) and direction. Velocity can be positive when an object is moving in one direction, and negative when it is moving in the opposite direction.
Acceleration, on the other hand, is the rate at which an object's velocity changes over time. Like velocity, acceleration is also a vector quantity with magnitude and direction. Positive acceleration means that an object is speeding up, while negative acceleration indicates that it is slowing down.
Now, considering a car traveling on a highway, let's address your first question: Can it have a negative velocity and a positive acceleration at the same time?
Yes, it is indeed possible for a car to have a negative velocity and a positive acceleration simultaneously. For example, imagine a car traveling in the negative direction with a speed of 50 km/h. If it starts to accelerate in the positive direction at 10 km/h², its velocity will still be negative, but its acceleration will be positive. In this scenario, the car is slowing down (negative velocity) but at an increasing rate (positive acceleration).
Moving on to your second question: Can the car change the direction of its velocity when traveling with constant acceleration?
Yes, it is possible for a car to change the direction of its velocity when traveling with a constant acceleration. This happens when the car's acceleration is in the opposite direction to its initial velocity. To illustrate this, let's consider a car moving in the positive direction with a certain velocity. If the car experiences a constant negative acceleration, it will eventually come to a stop and then start moving in the negative direction. As a result, the car changes the direction of its velocity while maintaining a constant acceleration.
In summary, a car can have a negative velocity and a positive acceleration simultaneously, and it can change the direction of its velocity when traveling with constant acceleration. These concepts can be understood by considering the definitions and characteristics of velocity and acceleration.