All Mechanics DOUBTS HERE!!!

[The Golden Girl =D]

Okay I'll do some Questions then ,Thanks Sir =]

[The Golden Girl =D]

Q.5.  An airplane is flying horizontally at 400m/s. A package is released and travels a distance of 2000 m horizontally BEFORE hitting the ground. Model the package as a particle and hence find the Height of the airplane above the ground.

Didn't know how to solve the Whole thing =,=

Q.6. A ball is thrown at 14m/s at an angle of elevation of 60. a) Find it's horizontal and vertical distances from the point of projection after ONE second. b) Find the direction of motion of the ball.

I can't seem to get the right answer for part b)  


Can someone answer it in details Please and I'd prefer it if you drew a Diagram , it'll make it easier for me to understand what you're doing =]

[astarmathsandphysics]

Here you go gg

[astarmathsandphysics]

Two acrobats, each of 64.0 kg, launch themselves together from a swing, holding hands. Their velocity at launch was 5.20 m/s and the angle of their initial velocity relative to the horizontal was 56.0 degrees upwards. At the top of their trajectory, their act calls for them to push against each in such a way that one of them becomes stationary in mid-air and then falls to the safety net while the other speeds away, to reach another swing at the same height at that of the swing they left. What should be the distance (in m) between the two swings?

[dk bose]

i have got an impossible doubt which i have tried 4 abt a week but was unable 2 solve it.it is 4m heinemann modular mathematics for edexcel as and a-level M1 text book,page 58,Review exercise 1, Question number 16.
the question is as follows-
A particle P moved in a straight line with constant retardation. At the instants when P passed through the points A,B and C it was moving with speeds 10m/s,7m/s and 3m/s respectively.
Prove that AB/BC=51/40.

[astarmathsandphysics]

For last question above see attachment

[dk bose]

i have got another doubt.the same textbook. Page no 147.Review exercise 2,question number 13.the question is as follows-
A block of mass 3 kg is pulled along a rough horizontal floor by a constant force of magnitude 20 N inclined at an angle 60 degrees to the upward vertical. The acceleration of the block has magnitude 2m/s.Calculate,to 2 dp the value of the coefficient of friction between the block and the floor.

[astarmathsandphysics]

When I get home in three hours, I will able to answer this with a diagram.

[astarmathsandphysics]

the block question answered

[dk bose]

Thanx, but i have come up with one more doubt.its 4m the same textbook,page no 59.Review exercise 1,Question number 20.the question is as follows-
A particle starts at rest at O and moves along Ox.During the first 4s of its motion it accelerates uniformly to a speed of 12m/s.the particle continues at this speed for 10s.It then decelerates uniformly,coming to rest after a further T seconds.Given that the total distance travelled is 180m, calculate T.

[astarmathsandphysics]

One mo

[astarmathsandphysics]

the answer i got is 2 2/3 s Strange nu,ber/

[dk bose]

But you have to get the answer as T=6s,i saw it 4m the back of the textbook.Please try the sum one more time and give me the correct solution to this problem.hey anyone plzzzzzz try this impossible sum and give me the solution as fast as possible!!!!!!!!!!!!!!!!!!! its urgent plzzzz!!!!!1111

[astarmathsandphysics]

It is 6/ For some stupid reason I said it travelled 140m 12m/s for 10 is actually 120
1/2*4*12+10*12+1/2*T*12=180
the answer is T=6

[dk bose]

one more doubt 2 go.its 4m edexcel june 2006 paper question number 5.its as follows-
A steel girder AB has weight 210N.It is held in equilibrium in a horizontal position by two vertical cables.one cable is attached to the end A.The other cable is attached to the point C on the girder,AC=90cm.The girder is modelled as a uniform rod,and the cables as light inextensible strings.
Given that the tension in the cable at C is twice the tension in the cable at A,find (a) the tension in the cable at A, (b) show that AB = 120cm.
A small load of weight W newtons is attached to the girder at B. the load is modelled as a particle.The girder remains in equilibrium in a horizontal position.The tension in the cable at C is now three times the tension in the cable at A. (c) Find the value of W.