The block 'a' can be made to slide down the slope by increasing its weight, increasing the dip of the slope, or by reducing the friction at the base of the block. Applying any one or all of these methods will help the block to overcome the friction and start moving downhill.
To make block 'a' slide down the slope, there are several methods that could be employed. These are:
- Increase the weight of 'a' without changing the friction on the slope. Increasing the weight increases the downward force due to gravity along the slope, which may help overcome the friction.
- Increase the slope dip so there is a larger shear component, meaning the angle of the slope is greater, which in turn increases the component of the weight acting down the slope.
- Reduce the friction at the base of the block, which decreases the resistance against the motion caused by the block's weight acting down the slope.
If you apply any one of these methods, or a combination of all, you would succeed in making the block slide down the slope. Answer (d) 'all of the above' is correct because each action would contribute to the block beginning to slide or sliding faster down the incline.