Question

An electron has a constant acceleration of +2.9 m/s^2. At a certain instant its velocity is +8.7 m/s. What is its velocity (a) 1.6 s earlier and (b) 1.6 s later?

Answer 1

Answer on Question #51364 - Physics - Mechanics | Kinematics | Dynamics

1. An electron has a constant acceleration of $+2.9 \, \mathrm{m/s^2}$ . At a certain instant its velocity is $+8.7 \, \mathrm{m/s}$ . What is its velocity (a) 1.6 s earlier and (b) 1.6 s later?

Let check the dimension: $\left[v_{1}\right] = \left[v_{2}\right] = \frac{m}{s} -\frac{m}{s^{2}}\cdot s = \frac{m}{s}.$

Let evaluate the quantity:

$$\nu_ {1} = 8. 7 - 2. 9 \cdot 1. 6 = 4. 0 6 \left(\frac {m}{s}\right), \quad \nu_ {2} = 8. 7 + 2. 9 \cdot 1. 6 = 1 3 \cdot 3 4 \left(\frac {m}{s}\right).$$

Answer: $4.06\frac{m}{s}$ ， $13.34\frac{m}{s}$

http://www.AssignmentExpert.com/