A motor car is going due north at a speed of \(50\ \text{km/h}\). It makes a \(90°\) left turn without changing the speed. The change in the velocity of the car is about:
1. \(50\ \text{km/h}\) towards west
2. \(70\ \text{km/h}\) towards south-west
3. \(70\ \text{km/h}\) towards north-west
4. zero

Consider the motion of the tip of the minute hand of a clock. In one hour:

Choose the correct option from the given ones:
1. (a) and (b) only
2. (b) and (c) only
3. (c) and (d) only
4. (a) and (d) only