575 - Physics Questions Answers
when two plane mirror inclined to each other at an angle 60degree , the number of image =?
please explain with ray diagram .
angle is 60
if object is placed symmetrical then images = 360/60 - 1 = 5
if unsymmetrical then 360/60 = 6
a boat is moved uniformily by pulling with force p=240n,q=200n .what must be the inclination of the resultent force with p and q to have resultent r=400.
In this problem r is the resultant of p and q, let the angle between r and p is α and r and q is β then
p = r sin β/sin(α+β) (1) and q = r sinα/sin(α+β) (2)
so p/q = sinβ/sinα
and according to given condition p/q = 6/5 so sinβ = 6k and sinα = 5k
now obtain cos function and solve it.
a cyclist is moving due east with a velocity of 10 km/h there is no wind air and rain appear to fall at degree vertival calculate the speed of rain.
Question is not submitted properly, angle is not given
let the angle is θ degree
then v(man) = 10i
and v(rain) = -vj i and -j are the directions for man and rain
so v(rain w.r.t. man) = -vj-10i
so tanθ = 10/v so v = 10 cotθ
θ is measured from vertical
A body is moving on a circle of radius 80m with a speed 20m/s which is decreasing at the rate of 5m/s2 at an istant. What is the angle made by its acceleration with its velocity?
You should write that calculate
What is the angle made by its acceleration with its velocity at the instant for which conditions are given.
solution
centripetal acceleration = 20*20/80 = 5 m/s2
tangential acceleration = 5 m/s2
so angle = tan-1(5/5) = 450
A body is projected with a velocity of 20m/s and at an angle of 30° with the ground. The change in the direction of its velocity cannot be (during its motion).
I think options are necessary for this problem.
but if we analyse we can say that the angle will be between 0 and 120 degree
Q.On a spring balance,
(i)10N force is applied on both the ends
(ii)10N force is applied on one end & no force on the other end.
(iii)10N is applied on one end and 20N is applied at the other.
Calculate the reading of the spring balance in each case.
Please reply fast.
i) 10 N
ii) 0 N, and it will be accelerated
iii) 10 N, and it will be accelerated
Sir,
please explain in detail how friction helps in walking?Please involve all the action and reaction forces involved in the process..Also what is the reason that we can't walk on a frictionless surface?
in accelerated motion friction will be forward and due to the same reason we take small steps when we walk in ice due to reduce friction. Without friction you can not accelerate or retard on the surface.
when we throw a shotput ball it covers a very less distance and when we throw a rubber ball it covers a larger distance.
the reason behind this well known to everyone that the shotput ball has more mass as compared to the rubber ball.
But when throw a paper ball it covers the least diatance why?
for this motion 0-R = ma
so retardation = R/m
for less mass retardation will be more
in the case of shotput
mu + impulse given = mv
so v = u + {impulsegiven/m}
so more mass will gain less velocity in comparison to less mass on applying same impulse.
can the linear speed of two objects be different if they have the same angular speed?
angular speed depends on the distance from pivot also so v may be same or different
formula affilated is v = r ω
A body is projected with a velocity 'u' making an angle α with the horizontal. Its velocity when it is perpendicular to the initial velocity vector is:
A. ucotα B. utanα C. usinα D. ucosα
component of gravity perpendicular to the final direction is gsinθ so by equation
v=u+at
0 = u -gsinθt
so t = u/gsinθ
now along final direction v = 0+gcosθt on putting the value of t we get v = gcosθu/gsinθ = ucotθ