1.1. Extended tier only

Salmon are born in freshwater rivers, spend most of their lives in the sea, but return to freshwater rivers to breed. As they swim up rivers, they often have to jump up waterfalls.

Fig. 1.1 shows a salmon attempting to jump up a waterfall with a vertical height of 0.36 m.

Fig. 1.1 

The salmon has a mass of 1.84 kg.

The salmon leaves the water with a speed of 3.2 m/s.

Determine whether the salmon can make the height required for the jump.

1.2. Extended tier only

Another salmon of mass 2.2 kg tries to make the jump. 

Calculate the minimum speed with which the salmon would have to leave the water in order to reach the height required.

speed = .................................... 

1.3. The salmon swim far upstream and encounter a high waterfall.

 The salmon attempts to jump to the top of the waterfall, but fails, and performs a somersault during the decent. The salmon straightens out before it enters the water as shown in Fig. 1.2.

Discuss whether the speed of entry into the water is greater than, less than or equal to the speed with which it leaves the water. Ignore any effects of air resistance.

1.4. The temperature of the water at the bottom of a waterfall is greater than the temperature of the water at the top. 

Suggest why this is the case.