Pls solve all these questions
Answers
Answer:
Q.2.ans.Initial velocity of object (u) = 15m/s
Final velocity of object (v) = 10 m/s
Time taken (t) = 2 seconds
As, we know formula for acceleration is -
(v-u)/t
So, Acceleration = (10-15)/2
= -5/2
= -2.5 m/s²
Answer) Acceleration of body is -2.5 m/s²
Q.3.ans.The magnitude of displacement is 2 [A/ π] and ratio of distance to displacement is π : 2
Consider r as the radius of semicircular path.
When a body covers distance of x meter along a circular path, distance covered by body will be 2π r. But here body is covering distance along semicircular path. So distance covered by body will be π r.
Now Let’s find the displacement of the body.
Distance covered by body, A = π r ------(1)
Displacement = Diameter of the semicircular path = 2r ----- (2)
Putting the value of r from equation (1) to equation (2),
Displacement = 2 [A/ π]
Ratio of distance to displacement = A : 2A/ π = π : 2
Q.4.ans.Given:
Initial velocity =u=5m/s
Acceleration=a=-2.5m/s2
Time =t=4sec
Displacement =s =?
From Second equation of motion:
S=ut+ 1/2 at^2
=5×4+1/2*(-2.5)4*4
=20-25*16/2*10
=20-20
=0 m
Q.5.ans.Total distance = 30+90=120
if avg. spd is 60 km/h then total time to cover the dist. is 2 hour.
avg spd.= (30+x)/2
distance=spd * time
120=(30+x)/2*2
120=30+x
x=120-30=90
i.e spd = 90 km/h
Q.6.ans.1) The motion of a freely falling body and a vertically thrown up body are theexample of uniform accelaration. 2) The motion of a ball rolling down an inclined plane is another example of uniform accelaration. a body has a uniformaccelaration if its velocity changes at a uniform rate.
Q.7.ans.a)If distance time graph is a straight line parallel to the time axis, the body is said to be at rest.
b)If speed time graph is a straight line parallel to the time axis, the object is said to be moving uniformly.
Q.8.ans.i)When body is stationary:-
=>Distance time graph for a body at rest is a straight line parallel to time axis.
ii)When body is moving with uniform speed:-
=>The distance time graph for a body moving with constant speed is straight line.
iii)When body is moving with non-uniform speed:-
=>The distance time graph for a body moving with non-uniform speed is curved line.
And the graphs are above so u can refer it
Hope it helps uh...✌️✌️✌️
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