All Mechanics DOUBTS HERE!!!

[astarmathsandphysics]

the m1 09 questions

[dk bose]

one more doubt. the question is as follows.-
Two particles A and B, of masses 0.4kg and 0.3kg respectively.,are connected by a light inextensible string which passes over a smooth light fixed pulley.The particles are released from rest with the string taut and the hanging parts vertical.Calculate-
(a) the acceleration of A.
(b) the tension in the string.
The particles continue to move in this system until the instant when they have each acquired speed 3.5m/s.At this instant both A and B are 1.4m above horizontal ground and the string is cut.Give that each particle now moves freely under gravity find the difference in the times,measured from the instant when the string is cut,for A and B to reach the ground.   

[dk bose]

one more sum to go.the question is as follows-
A particle moves down a line of greatest slope of a rough plane which is inclined at 30 degress to the horizontal.The particle starts from rest and covers 3.5m in time 2s.Find the coefficient of friction between the particle and the plane.

anyone plzzzzzzzz !!!!!Try to solve my these threee doubts and post me the solutions as fast as possible!!!!!!!!!!!! itzzzzzzzzzz urgent !!!!!!!!!! 

[astarmathsandphysics]

morning

[astarmathsandphysics]

here

[dk bose]

where is the answer for my first question????these are just the answers for two questions??plzzz solve my first question and give the solutions as fast as possible!!!!!!!!!!

[astarmathsandphysics]

Keep your dress on dovey. On it now.

[astarmathsandphysics]

The particle question

[dk bose]

one more doubt.the question is as follows-
Two joggers,A and B, are running with constant velocity on level parkland. At a certain instant, A and B have position vectors (-60i+210j)m and (30i-60j)m respectively,referred to a fixed origin O.Ninety seconds later,A and B meet at the point with position vector (210i+120j)m.
(a) Find,as a vector in terms of i and j the velocity of A relative to B.
(b) Verify that the magnitude of the velocity of A relative to B is equal to the speed of A.

[dk bose]

one more doubt.the question is as follows-
A particle,P,of mass 0.3kg,is moving in a straight line on a rough horizontal floor.The speed of P decreases from 7.5m s^-1 to 4 m s^-1 in time T seconds.Given that the coefficient of friction between P and the floor is 1/7(one divided by 7) find:
(a) the magnitude of the frictional force opposing the motion of P.
(b) The value of T.

try to solve these two sums as give me the solutions as fast as possible!!!!!!! itzzzz urgent!!!!!!!!!!!!

[astarmathsandphysics]

answered

[dk bose]

one more doubt.the question is as follows-
(a)A ball of mass 0.3kg is released from a point at a height of 10m above horizontal ground.After hitting the ground the ball rebounds to a height of 2.5m.calculate,in N s, the magnitude of the impulse of the force exerted by the ground during the impact.
(b) State two assumptions you have made about the ball and the forces acting on it in order to solve part(a).

[astarmathsandphysics]

here. I didn't notice this until a few mins ago

[dk bose]

A train stops at two stations 7.5km apart.Between the stations it takes 75s to accelerate uniformly to a speed of 24m s^-1,then travels at this speed for a time T seconds before decelerating uniformly for the final 0.6km.
(a)Sketch a speed-time graph for this journey.Hence,or otherwise,find
(b) the deceleration in m s^-2 of the train during the final 0.6km,
(c) the value of T,
(d) the total time for the journey.

[dk bose]

A particle moves with constant acceleration along the straight line OLM and passes through the points O,L and M at times 0s,4s and 10s respectively.Given that OL=14m and OM=50m,find
(a) the acceleration of the particle.
(b) the speed of the particle.

anyone plzz solve these two sums and give me the solutions as fast as possible!!!!!!!!!!!