A 200-kg granite rock (? = 2700 kg/m3) is dropped into a lake. A man dives in and tries to lift the rock. Determine how much force the man needs to apply to lift it from the bottom of the lake. Do you think he can do it?

We calculated the mass of water in a large reservoir. We will now consider the pressure and force acting on the dam retaining water. The dam is 500 m wide, and the water is 80.0 m deep at the dam. (a) What is the average pressure on the dam due to the water? (b) Calculate the force exerted against the dam and compare it with the weight of water in the dam (previously found to be 1.96X10 N).

Please solve this question handwriting

Your engineering firm is asked to specify the maximum load for theelevators in a new building. Each elevator has a mass 490 kg when empty and maximumacceleration 2.24 m/s2. The elevator cables can withstand a maximum tension of 19.5 kN beforebreaking. For safety, you need to ensure that the tension never exceeds two-thirds of that value.What is the maximum load that the elevator can safely carry? How many70-kg people is that?Briefly but clearly explain the reasoning for your choice of the sign of the acceleration.