An object is thrown vertically upwards and reaches a height 20m. Calculate. A)the velocity of the object. B)the time taken to reach the highest point.(g=10m/s^2
Answers
Answer:
A) 20 m/ s B) 4 s
Explanation:
given height i.e s = 20 m
A) velocity of the object
v = 0 [ at highest point the velocity of object is always zero ]
v = u - 2as ( - ve sign because it is thrown in upward direction )
0 = u² - 2 × 10 ×20
0 = u² - 400
u = √400
u = 20 m/s
B) time
T = 2u/g
= 2 × 20 / 10
= 4 s
Explanation:
Given that,
" An object is thrown vertically upwards and rises to a height of 20 m. "
Here,
Initial velocity, u = ? m/s
Final velocity, v = 0 m/s [ since velocity at maximum height is "0" ]
Acceleration, a = g = - 10 m/s^2 [ since against gravity ]
Distance, s = 20m
we need to find,
(i) the velocity with which the object was thrown upwards
use 3rd law of motion
v^2 - u^2 = 2as
0^2 = - u^2 = 2 (-10) (20)
u^2 = 400
u = 20 m/s
(ii) The time taken by the object to reach the highest point
use first equation of motion
v = u + at
0 = 20 - ( 10) t
10t = 20
t = 2 s
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