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A body of mass 2 kg travels according to the law x(t)=pt+qt²+rt³,where p=3 m/s,q=4 m/s² and r=5 m/s³.The force acting on the body at t=2 s is
Options
(a) 136 N
(b) 134 N
(c) 158 N
(d) 68 N
Correct Answer:
136 N
Explanation:
m = 2 kg, x = pt + qt² + rt³
⇒ dx/dt = p + 2qt + 3rt²
d²x/dt² = 2q + 6rt = acceleration(a)
At t=2s,
a = 2q +12r = 2 x 4 + 12 x 5
= 68 m/s²
F=ma = 2 x 68 = 136 N.
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Topics: Laws of Motion
(103)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- Identify the pair whose dimensions are equal
- Four indentical thin rods each of mass M and length l, form a square frame
- A proton beam enters a magnetic field of 10⁻⁴ Wb/m² normally. If the specific charge
- The charge flowing through a resistance R varies with time t as Q=at-bt²,
- The potential differences across the resistance, capacitance and inductance
Topics: Laws of Motion (103)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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