The letter corresponding to the best or most nearly correct answer. Each correct

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The letter corresponding to the best or most nearly correct answer. Each correct answer is worth A problem thet has two or more answer circled will be considerd incorrect and will you will get Mark for it. Make sure to circle only one letter. e velocity of a particle moving along the x axis vanes in time according to the expression (t) = (40 + 5t^2) m/s, where f is in seconds. The acceleration of the particle at t = 2 s is 5m/s^2 20 m/s^2 minus20 m/s^2 minus25 m/s^2 A truck covers 30.0 m in 5.0 s while smoothly slowing down to a final speed of 2.0 m/s. Its Acceleration is. minus0.45 m/s^2 minus1.60 m/s^2 0.60 m/s^2 0.45 m/s^2 The velocity graph of a particle moving along the x-axis is shown in the figure. Assuming x = 0 at t = the algebraic expressions for the velocity of the particle as a function of time is then v(t) = 50 minus l0t v(t) = 50t minus 10t^2 v(t) = 50t minus 5t^2 v(t) = minus10t A ban launched from ground level with an initial velocity of 30 m/s and s 1.54 seconds later 40.0 meters away from the launch point. The angle at which the ball is launched is 30 60 45 15

Explanation / Answer

1.

Acceleration is the derivative of velocity because it represents the change in velocity per unit of time.

V = 40 + 5t^2

dV/dt = 10t

Thus if t = 2, acceleration is 20 m/s^2

2.solution

Distance x = 35.0 m
Time t = 8.00 s
Final speed v = +2.80 m/s

Let acceleration = a
a = (v - u)/t

Let original speed = u

Average speed = x/t
For constant acceleration, average speed = (v + u)/2
Therefore,
(v + u)/2 = x/t
Or v + u = 2x/t
Or u = (2x/t) - v
Or u = (2*30/5) - 2.0
Or u = 12 - 2.0
Or u = 10m/s


acceleration = a
a = (v - u)/t
Or a = (2.0 - 10.0)/5 = -8 / 5 = -1.6 m/s^2

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