1
JEE Main 2019 (Online) 9th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The position of a particle as a function of time t, is given by
x(t) = at + bt2 – ct3
where a, b and c are constants. When the particle attains zero acceleration, then its velocity will be :
A
$$a + {{{b^2}} \over {c}}$$
B
$$a + {{{b^2}} \over {4c}}$$
C
$$a + {{{b^2}} \over {3c}}$$
D
$$a + {{{b^2}} \over {2c}}$$
2
JEE Main 2019 (Online) 9th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The position vector of a particle changes with time according to the relation $$\overrightarrow r (t) = 15{t^2}\widehat i + (4 - 20{t^2})\widehat j$$
What is the magnitude of the acceleration at t = 1 ?
A
50
B
25
C
40
D
100
3
JEE Main 2019 (Online) 8th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A particle starts from origin O from rest and moves with a uniform acceleration along the positive x-axis. Identify all figures that correctly represent the motion qualitatively. (a = acceleration, v = velocity, x = displacement, t = time) JEE Main 2019 (Online) 8th April Evening Slot Physics - Motion in a Straight Line Question 89 English 1 JEE Main 2019 (Online) 8th April Evening Slot Physics - Motion in a Straight Line Question 89 English 2 JEE Main 2019 (Online) 8th April Evening Slot Physics - Motion in a Straight Line Question 89 English 3 JEE Main 2019 (Online) 8th April Evening Slot Physics - Motion in a Straight Line Question 89 English 4
A
(B), (C)
B
(A)
C
(A), (B), (C)
D
(A), (B), (D)
4
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
A passenger train of length 60 m travels at a speed of 80 km/hr. Another freight train of length 120 m travels at a speed of 30 km/hr. The ratio of times taken by the passenger train to completely cross the freight train when : (i) they are moving in the same direction , and (ii) in the opposite direction is :
A
$${{25} \over {11}}$$
B
$${3 \over 2}$$
C
$${{11} \over 5}$$
D
$${5 \over 2}$$
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