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← JEE Main 2026 · 2 Apr · Shift 1
PhysicsSingle correct+4 / -1Question 28 of 75

JEE Main 2026 · 2 Apr · Shift 1, Physics question 28

The velocity of a particle is given as v⃗=−xi^+2yj^−zk^\vec v=-x\hat i+2y\hat j-z\hat k m/s. The magnitude of acceleration at point (1,2,4)(1,2,4) is ________ m/s².

Choose one option
Answer and worked solution

Official answer: B

Acceleration. ax=dvxdt=−vx=xa_x=\frac{dv_x}{dt}=-v_x=x, ay=2vy=4ya_y=2v_y=4y, az=−vz=za_z=-v_z=z.

At (1, 2, 4). a⃗=(1,8,4)\vec a=(1,8,4), so ∣a⃗∣=1+64+16=9|\vec a|=\sqrt{1+64+16}=9 m/s².

(B)