Physics PDF - Motion Calculations

(ii) Velocitv * Displacement Time taken 200 km towards North sh = 40 km/h towards North So, the velocity (or average velocity) of the car is 40 km/h torrards North. A bus covers a distance of 250 km from Deihi to faipur towards \{est in 5 hours in the morning and returns to Delhi in the evening cove...

(ii) Velocitv * Displacement Time taken 200 km towards North sh = 40 km/h towards North So, the velocity (or average velocity) of the car is 40 km/h torrards North. A bus covers a distance of 250 km from Deihi to faipur towards \{est in 5 hours in the morning and returns to Delhi in the evening covering the same distance of 250 km in the same time of 5 hours. Find (a) average speed, and (b) average velocity, of the bus for the whole journey. f[@ trl Average speed - Total distance travelled Total time taken 250 km + 250 km 5 h+s h 500 km = ,* : 50 kmih Thus, the average speed of the bus for the whole journey (both ways) is 50 kilometres per hour. (il) In this case, the bus travels 250 km from Delhi to )aipur towards West and then comes back to starting point Delhi in the leverse direction. So, the total displacement (or total distance travelled in a specified direction) will be 250 km - 250 km = 0 km. Now, Average velocitY ' = Total disolacement * Total time taken 250 km-250 km 5h+5h _ Okrn 10h = 0 km/h Thus, the average velocity of the bus for the whole journey (both ways) is 0 kilornetres per hour. No direction can be stated in this case of zero veiocity. ACC When the velocity of a body is increasing, the body is said to be accelerating. Suppose a car starts off from rest (initial velocity is zero) and its velocity increases at a steady rate so that after 5 seconds its velocity is 10 metres per second. Now; in 5 seconds the velocity has increased by 10 - 0 = 10 metres per second and in 1 second the velocity increases Uy ,5I = 2 metres per second. In other words, the rate at which the velocity increases is 2 metres per second every second. The car is said to have an acceleration of 2 metres per second per second. This gives us the following definition of acceleration: 26 lVotion