Final answer:
A plane moving at a constant speed of 5000 km/hr has zero acceleration, while a car that takes a turn at a constant speed will experience centripetal acceleration. To illustrate, a car on a curve with a 500 m radius going 90 km/h has a centripetal acceleration of 1.25 m/s², which is smaller than the acceleration due to gravity.
Step-by-step explanation:
If a plane moves with a constant speed of 5000 km/hr, its acceleration is zero because acceleration is defined as the rate at which velocity changes, and the velocity (speed and direction) of the plane isn't changing. On the other hand, if a car is moving at a constant speed but takes a turn at the end of the road, it will have acceleration; specifically, centripetal acceleration, which is always directed towards the center of the curve it is following.
For example, let's calculate the centripetal acceleration of a car taking a curve. The car follows a curve of radius 500 m at a speed of 25.0 m/s (about 90 km/h). The magnitude of the car's centripetal acceleration (ac) is calculated using the formula ac = v2/r, where v is the velocity and r is the radius of the curve. Plugging in the values, ac = (25.0 m/s)2/500 m = 1.25 m/s2. This acceleration is due to the change in direction of the car's velocity and it acts towards the center of the curve.
To compare this with acceleration due to gravity (g = 9.81 m/s2), we can see that the centripetal acceleration is much smaller than the gravitational acceleration. In a fairly gentle curve taken at highway speed, the car experiences an inward pull that is a fraction of the force that we experience due to gravity constantly pulling us down.