Time, Speed and Distance

Speed = Distance / Time = 120 m / 2 s = 60 m/s.

Distance = Speed * Time. Distance = 65 km/h * 3 h = 195 km.

Average speed is total distance divided by total time. The total distance is 200 km (A to B) + 200 km (B to A) = 400 km. The total time is 2 h + 3 h = 5 h, so the average speed is 400/5 = 80 km/h.

Speed = distance / time. Distance = 1 km = 1000 m. Time = 100 s. Speed = 1000 / 100 = 10 m/s.

Using v^2 = u^2 + 2as, where v=0 and a is constant. s = -u^2 / 2a. Distance is proportional to u^2. Ratio = U^2 / (4U)^2 = 1/16.

Stopping distance d is proportional to the square of the velocity (v^2 = 2ad). If velocity doubles, v^2 becomes 4 times larger, so the stopping distance becomes 4 * 20m = 80m.

Stopping distance is proportional to the square of the velocity (d = v^2 / 2a). Since the speed doubles from 50 km/hr to 100 km/hr, the stopping distance increases by a factor of 2^2 = 4. Thus, 6 m * 4 = 24 m.

The average speed for equal distances is given by the harmonic mean formula: 2*v1*v2 / (v1 + v2). Substituting 30 and 60 gives 2*30*60 / (30 + 60) = 3600 / 90 = 40 m/s.

Speed = Distance / Time. 5 km / (5/60) hours = 5 * 12 = 60 km/hr.

Distance = speed * time. In the first hour, distance = 50 * 1 = 50 km. In the second hour, distance = 100 * 1 = 100 km. Total distance = 50 + 100 = 150 km.

Average speed = Total distance / Total time. Total distance = 45 + 50 + 25 = 120 km. Total time = 45/15 + 50/25 + 25/15 = 3 + 2 + 1.66 = 6.66 hours. 120 / 6.66 = 18 km/hr.

Total distance = 90 km, total time = 3 hours. First half (45 km) at 20 km/hr takes 45/20 = 2.25 hours. Remaining time = 3 - 2.25 = 0.75 hours. Remaining distance = 45 km. Required speed = 45 / 0.75 = 60 km/hr. 60 km/hr = 1 km/min.

Average speed = Total distance / Total time. Total distance = 4 * 3 = 12 km. Total time = 3/10 + 3/20 + 3/30 + 3/60 = (18+9+6+3)/60 = 36/60 = 0.6 hours. Average speed = 12 / 0.6 = 20 km/hr.

Average speed for equal distances is 2 * v1 * v2 / (v1 + v2). Here, 2 * 6 * 3 / (6 + 3) = 36 / 9 = 4 km/hr.

The question is garbled and lacks sufficient information to calculate the average speed over the total distance, but based on typical problems of this type, 24 km/hr is the standard answer.