Mechanics | Relativity Answers

An alarm clock is dropped off the edge of a tall building. You, standing directly under it, hear a tone of 1350 Hz coming from the clock at the instant it hits the ground (you jumped out of the way at the last moment- whew!) Since you know the building is 25.0 m tall, you can find out what the frequency of the alarm would be if you had just held it in your hands. What would that frequency be?

A boat is heading north as it crosses a wide river with a speed of 8.00 km/h relative to the water. The river has a uniform velocity of 6.00 km/h dues east. Determine the magnitude and direction of the boat's velocity with respect to an observer on the riverbank. (Note write all the possible direction of the motion)

A hockey puck with an initial speed of 5.0 m/s coasts 50 m to a stop across the ice. If the force of friction on the puck has a magnitude 0.12 N, what is the puck’s mass?

What is diffrential form of centre force.

What is central force

8 A plank AB has mass 10kg and length 6m. It is held in equilibrium in a horizontal position by two ropes attached at the points C and D, where AC= 1 m and DB = 2m. The plank can be modelled as a uniform rod and the ropes as light strings. a Work out: i the tension in the rope at C ii the tension in the rope at D. A mass of 5kg is placed on the plank at a distance xm from C, between Cand D. The mass can be modelled as a particle. Given that the plank remains in equilibrium in the horizontal position, b find, in terms of x, an expression for the tension in the rope at D. The rope at D will break if the tension exceeds 10g N. The rope at C cannot break. e Work out the range of possible values of x.

1. A uniform rod of length 8 m and weight 50 N rests on a support that is 2m from A. The rod is held in a horizontal position by a force F that acts vertically downwards at A. a.Work out the magnitude of F. b.Work out the reaction at the support. 2. A uniform rod of length 7 m and weight 100N rests horizontally on two supports. Work out the values of the reactions R1, and R2, acting at the supports. 3. A uniform rod AB of mass Mkg and length Im, is held horizontally in equilibrium by two vertical strings attached at points A and C where AC:CB= 3:1. Find, in terms of m, the tensions T, and T, in the strings attached to the rod at A and C respectively. 4. A uniform rod AB, of weight 30N and length 6m, sits horizontally in equilibrium on two supports at points C And D as shown in the diagram. The reactions of the supports on the rod at points C and D are Rc and Rd, respectively. Given that Rc = 4Rd, work out the length x.

What is differential form of central force motion.

What is third equation of motion.

What is second equation of motion.