help@askiitians.com

+91-87964 74404

Grade 11Mechanics

In the following answer to the below question how did U → = (5 cos(20°) , 5 sin(20°)) come..what is the formula used??
QUES-The magnitudes of two vectors U and V are equal to 5 and 8 respectively. Vector U makes an angle of 20° with the positive direction of the x-axis and vector V makes an angle of 80° with the positive direction of the x-axis. Both angles are measured counterclockwise. Find the magnitudes and directions of vectors U + V and U - V.
SOLUTION -Let us first use the magnitudes and directions to find the components of vectors U and V.
U → = (5 cos(20°) , 5 sin(20°)

9237929

7 Years agoGrade 11

2 Answers

Arun

7 Years ago

Dear student

here velocity is divided in two components named horizontal component (5 cos 20) and vertical component (5 sin20)

Piyush Kumar Behera

7 Years ago

In the above solution posted for the question actually resolves the vector U into horizontal and vertical componesnt.

To make it more clear,

The horizontal component of any vector can be found out by multiplying the magnitude of the vector multiplied the cos of the angle made by the horizontal.

Similarly,The vertical component of any vector can be found out by multiplying the magnitude of the vector multiplied the sine of the angle made by the horizontal.

Here the values given in the brackets are horizontal and vertical components of the vector.

To solve the question ,

resolve U and V into horizontal and vertical components and add it as rectangular componests(i.e in terms of i and j)

Then add and subtract accordingly and find resaultant to get the answer of the question.

Hope it helps!!

Piyush Kumar Behera

IIT (ISM) Dhanbad

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