A car travelling at 72 km/h takes a U – turn in 10 seconds. What is the acceleration of the car ?

Sure, here are the steps to solve this problem:

Step 1: Convert the speed from km/h to m/s The car's speed is given as 72 km/h. We need to convert this to m/s because the standard unit of speed in physics is m/s. We know that 1 km = 1000 m and 1 hour = 3600 seconds. So, 72 km/h = 72 * 1000 / 3600 = 20 m/s.

Step 2: Calculate the final speed after the U-turn A U-turn means the car changes its direction by 180 degrees. However, the magnitude of the speed remains the same (assuming the car maintains a constant speed during the turn). So, the final speed of the car is also 20 m/s, but in the opposite direction. In terms of calculation, we consider this as -20 m/s.

Step 3: Use the formula for acceleration Acceleration is defined as the change in velocity divided by the time taken for the change. The formula is a = (v_f - v_i) / t, where a is acceleration, v_f is the final velocity, v_i is the initial velocity, and t is time.

Step 4: Substitute the values into the formula a = (-20 m/s - 20 m/s) / 10 s = -40 m/s / 10 s = -4 m/s².

So, the acceleration of the car is -4 m/s². The negative sign indicates that this is a deceleration, i.e., the car is slowing down.