Grade 11Mechanics

A ball is thrown vertically upward from the 12m level with an initial velocity of 18m/s .At the same instant an open platform elevator passes the 5 m level,moving upward with a constant velocity of 2m/s.Determine -(a) when and where the ball will meet the elevator, (b)the relative velocity of the ball w.r.t.elevator when the ball hits the elevator

Anjana Sirothiya

9 Years agoGrade 11

1 Answer

Vikas TU

9 Years ago

Dear Student,

Initial relative velocity of ball with respect to elevator = 18 -2

= 16m/sec

Relative acceleration of ball with respect to elevator = -10-0

=-10m/sec^2

To meet the elevator ball has to travel a distance of 7m

S = -7m (downwards)

S = ut+1/2 at^2
-7 = 16t – ½ *10 *t^2
-7 = 16t – 5t^2

Solve for t

t = (16±√396)/ 10

Neglecting negative root

t = (16+√396)/10

Relative velocity at crossing

v = u+at

= 16 – 10 *((16+√396)/10)
= 16- 16-√396
=-36 m/sec

Cheers!!

Regards,

Vikas (B. Tech. 4^th year
Thapar University)

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

mechanics

1 Answer Available

Last Activity: 9 Months ago

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

11
21
31
41

mechanics

1 Answer Available

Last Activity: 9 Months ago

A metal strip clamped at one end vibrates with a frequency of 20 Hz and amplitude of 5 mm
at the free end, where a small mass of 2 g is positioned. determine
(i) The velocity of the end when passing through the zero position
(ii) The acceleration at maximum displacement
(iii) The maximum kinetic energy of the mass

mechanics

2 Answers Available

Last Activity: 3 Years ago

An object of mass m = 0.25 kg oscillates in a fluid at the end of a vertical spring of spring
constant kH = 85 N/m, see Fig.1. The effect of the fluid resistance is governed by the
damping constant b = 0.07kg/s.
(i) Find the period of the damped oscillation.
(ii) By what percentage does the amplitude of the oscillation decrease in each cycle?

mechanics

1 Answer Available

Last Activity: 3 Years ago

If a=x² find the displacement at t =3sec if body velocity at t= 0 sec is 0

mechanics

1 Answer Available

Last Activity: 3 Years ago

View all Questions

Anjana Sirothiya

1 Answer

Vikas TU

Other Related Questions on mechanics

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.11213141

If a=x² find the displacement at t =3sec if body velocity at t= 0 sec is 0

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

11
21
31
41