what can have a varying velocity and varying speed
Kind of a strange question, since every object can have a varying velocity while having a varying speed.
When you talk about speed, you are referring to a quantity (e.g. John travels with a SPEED of 2 mph).
When you talk about velocity, you also talk about a quantity, but you add a direction to it (e.g. John travels with a VELOCITY of 2mph in a northbound direction).
In other words: When you talk about speed, you only need a quantity. When you talk about velocity you need a quantity and a direction.
So, when the speed of an object changes, its velocity automaticly changes with it.
Remember that when velocity changes, this doesn't mean that your speed needs to change as well. It's also possible that while your speed remains constant, the direction of your velocity changes (and so does the velocity itself).
Anything can. Except for light in a vacuum
The concept of velocity and speed can sometimes be confusing, so let's clarify their definitions first before identifying what can have varying velocity and varying speed.
Velocity is a vector quantity that encompasses both speed and direction. It describes the rate at which an object changes its position over time in a specific direction. It is denoted by a magnitude (speed) and a direction (e.g., 50 km/h north).
Speed, on the other hand, is a scalar quantity that refers to the rate at which an object covers distance. It is the magnitude of velocity and does not consider direction. Speed is denoted without any specific direction (e.g., 50 km/h).
Now, in terms of objects or phenomena that can have varying velocity and varying speed:
1. A Car on a Curved Road: When a car travels on a curved road, its velocity (including both speed and direction) changes continuously. The car must adjust its speed and change direction as it goes around bends, resulting in varying velocity and, consequently, varying speed.
2. Projectile Motion: When an object is launched into the air at an angle, like a basketball being thrown, it follows a curved trajectory due to the influence of gravity. During its flight, the object's velocity constantly changes both in terms of speed (as it moves up and down) and direction (as it follows a parabolic path).
3. Cyclist Going Uphill: When a cyclist is pedaling uphill, the direction of their velocity is upward, opposite to the force of gravity. As a result, the cyclist's speed may decrease while their velocity changes due to the uphill incline.
4. A Roller Coaster: Roller coasters are designed with various twists, loops, and turns that change the direction and speed of the riders continuously. As the coaster accelerates or decelerates during the ride, the velocity and speed of the passengers vary accordingly.
In summary, any object or system that experiences changes in direction or speed can have varying velocity and varying speed. This often occurs in situations involving curved paths, changes in elevation, or when forces act upon an object to alter its motion.