Motion in a vertical circle and conservation of energy
A stone tied to a string of length l is whirled around a vertical circle with the other end of the string at the centre. At a certain instant of time the stone is at the lowest position and has a speed u. What is the magnitude of change in its velocity as it reaches a position where the string is horizontal?
Answer:
Let’s assume that the potential energy at the lowest position be zero. So, when the string is horizontal, the stone has risen by a vertical height l, the length of the string which is also the radius of the vertical circle.
If v is the magnitude of velocity at the horizontal position, then according to the law of conservation of energy,
KE+PE at the lowest position = KE+PE at the horizontal position
From the equation above, v-u can be calculated.
The following links will help you for deeper understanding and you can browse through some solved problems from the topic too.
- http://www.tutorvista.com/content/physics/physics-iii/motion-laws/vertical-circle-motion.php
- http://www.goiit.com/posts/show/813363/work-derivation-804230.htm
- http://www.mathsrevision.net/alevel/pages.php?page=85
Categories: Answers, ANSWERS TO QUESTIONS FROM VISITORS, CLASS XI, energy loss, energy motion, Exam Help, General Physics, IIT JEE, Interesting Questions, motion work, Physics Homework, Plus Two Physics, power and energy, Problem Solving, Problems, Soved Numerical Problems Tags: Auto, centre, conservation of energy, law of conservation, law of conservation of energy, magnitude, motion, motion laws, position, stone, vertical circle, vertical height
Motion of connected system – A Numerical problem
A mass 5kg descending vertically,draws up a mass of3kg by means of a light string passing over a pulley.At the end of 4 seconds,the string breaks.How much higher 3 kg mass would go?
Post your solutions as comments to this post
Answer will be posted soon once we get responses from visitors
Categories: Plus Two Physics Tags: Auto, Draft, kg, light string, mass, motion, numerical, numerical problem, pulley, system
Homework from Projectile Motion
A projectile is projected at an angle theta with horizontal with speed u . If air resistance is taken in account , the angle with vertical at the time of hitting the ground will be a)more than (90 + theta) b)less than (90 – theta) c)(90 + theta...
Categories: KINEMATICS Tags: air resistance, angle theta, answer, ground, hitting the ground, homework, motion, Projectile, Projectile motion, speed, theta
Numerical Problem from Motion of Connected systems
Two blocks A and B of mass m1 and m2 respectively are kept in contact on a frictionless table.The experimenter pushes the block A from behind so that the blocks accelerate. If the block A exerts a force F on the block B,what is the force exerted by the experimenter on A. Incoming search terms:numericals on [...]
Categories: Ask Physics, Connected, connected systems, experimenter, Force, m1, m2, Mechanics, Project Tags: connected systems, experimenter, m1, mass, motion, numerical, numerical problem, Physics, problem, search terms
Solving problems on Laws of Motion
Sir,in solving problems of laws of motion ,is it mandatory to take that direction as +ve in which acceleration acts?(i.e should i subtract other forces acting on a body from the forces that is acting towards the acceleration) (Pranay Talukdar asks) Answer: In general, we take the forces in the direction of acceleration (I.E, ENHANCING [...]
Categories: Ask Physics, Project Tags: acceleration, answer, body, constraint problems, direction, direction of acceleration, ENHANCING, form, law of acceleration, laws of motion, motion, Physics, talukdar
An online quiz for Class 9 Physics – Force and Motion
Attempt this quiz from force and motion. This is primarily aimed at CBSE Class9 students. A Multiple Choice Quiz from Force The page will open in a new window. Your score will be shown on top of page in percentage. You can attempt multiple times and can improve performance. Please post your comments if you [...]
Categories: Ask Physics Tags: choice quiz, force and motion, Match, motion, multiple choice, multiple times, Online, Physics, score, search terms
A Numerical Problem from Projectile Motion
A short is fired from a gun on the top of a hill 90m high with velocity 80m/s at an angle of 30 degree with the horizontal. Find the horizontal distance between the vertical line through the gun and the ponit where the shot strikes the ground? (Shilpa asked this question)
Answer:
Take Sy= -90m
ay= -g=-9.8m/s2
uy= u sin(30) =80 x 0.5 = 40m/s
Substitute in the eqn
s = ut + 0.5 at2
and find t
The horizontal distance Rx = horizontal velocity x time = U cos (30) x time
Substitute for u and t and get the answer
Categories: Answers, Ask Physics, Mechanics, Problem Solving, Problems, Project Tags: answer, hill, horizontal velocity, motion, numerical, numerical problem, ponit, Projectile motion, Substitute, x time
