Question

What is her velocity 2.9 s later in meters per second?

a) Speed = Distance × Time.
b) Velocity = Acceleration × Time.
c) Velocity = Displacement / Time.
d) Velocity = Speed × Time.

Answer 1

Using the equation for velocity with acceleration, the velocity of the runner is calculated to be 3.20 m/s after 2.9 seconds of deceleration from an initial 9.00 m/s with a deceleration rate of 2.00 m/s².

Step-by-step explanation:

To find out what the velocity of the runner is 2.9 seconds after decelerating from an initial velocity of 9.00 m/s at a rate of 2.00 m/s², we can use the equation for velocity when acceleration is involved. The equation is final velocity (v) = initial velocity (u) + acceleration (a) × time (t). We are given the initial velocity and acceleration, and we seek the final velocity after a certain time has elapsed.

Given that:

• Initial velocity, u = 9.00 m/s
• Acceleration, a = -2.00 m/s² (negative since it is deceleration)
• Time, t = 2.9 s

Plugging these values into the equation, we get:

v = u + (a × t)

v = 9.00 m/s + (-2.00 m/s² × 2.9 s)

v = 9.00 m/s - 5.80 m/s

v = 3.20 m/s

Thus, the velocity of the runner 2.9 seconds later is 3.20 m/s.