Pascal and Newton for Nav

1 Pascal of pressure is 1 Newton per metre squared i.e.$1Pa=1N/m^2$

L6FM m1 Blog Hwk 3

To be completed on paper with full working out. Total 30 marks.

1. Particles P and Q of mass 3m and 4m respectively are attached to the ends of a light inextensible string which passes over a smooth pulley. The masses hang with the string taut. The system is released from rest:

1. Find the acceleration of the system and state its direction

   [3 marks]

2. Find the tension in the string

   [3 marks]

3. Find the force exerted on the pulley by the string

   [3 marks]

4. Find the distance moved by Q in the first 4 seconds assuming that P does not hit the pulley

   [2 marks]

2. A ball is thrown vertically upwards from the top of an 80m high cliff with speed 15m/s. Find:

1. The time it takes to hit the sea below

   [3 marks]

2. The speed with which it hits the water

   [2 marks]

3. Particles P and Q have masses 2kg and 3kg and lie on the 2 slopes of a rough wedge. Particle P lies on the rough plane inclined to the right at 30 degrees. P is attached to Q via a light inextensible string which passes over a smooth pulley at the top of the slope. Q lies on the rough plane which is inclined at 45 degrees to the left. The plane upon which P lies has $\mu= 0.2$ and the plane upon which Q lies has $\mu= 0.1$. The system is released from rest.

1. Calculate the acceleration of the system and the tension in string.

   [8 marks]

2. Calulate the time it takes Q to travel 3m

   [3 marks]

4. Allegedly driving along at 70mph, my wife manages to convince me, 2 miles into a 3 mile section of motorway with average speed check cameras for 50 mph, that the cameras do indeed work. To what speed must I slow down to make my average over the 3 miles 50mph?

[3 marks]