during a football game, igor is 8.0m behind brian and is running at 7.0m/s^2 when brain catches the ball and starts to accrlerate away at 2.8m/s^2 from rest.

a) will igor catch brian

3 answers

To determine if Igor will catch Brian, we need to compare their positions as a function of time.

Let's assume t represents the time it takes for Brian to catch the ball and start accelerating away from rest.

For Igor:
Initial position (x_i) = 8.0m
Initial velocity (v_i) = 0 m/s (since he is running at a constant speed)
Acceleration (a_i) = 7.0 m/s^2 (positive because it's in the direction he is running)
Time (t) = unknown

For Brian:
Initial position (x_i) = 0 m (since he catches the ball at position 0)
Initial velocity (v_i) = 0 m/s (since he starts accelerating from rest)
Acceleration (a_b) = 2.8 m/s^2 (positive because he is accelerating away)
Time (t) = unknown

The distance traveled by Igor after time t can be given by:
x_i = 8.0m
v_i*t + 0.5*a_i*t^2 = 8.0m

The distance traveled by Brian after time t can be given by:
x_i = 0m
0.5*a_b*t^2 = 0m

Simplifying these equations, we have:
0.5*7.0*t^2 = 8.0
0.5*2.8*t^2 = 0

Solving the first equation:
3.5*t^2 = 8.0
t^2 = 8.0/3.5
t^2 ≈ 2.29
t ≈ √2.29
t ≈ 1.51s

Solving the second equation:
1.4*t^2 = 0
t^2 = 0/1.4
t^2 = 0
t = 0s

Since Brian starts accelerating from rest, it takes him 0 seconds (t = 0s) to catch the ball and start accelerating. However, it takes Igor about 1.51 seconds (t ≈ 1.51s) to reach the same position.

Therefore, Igor will not catch Brian.
how far the field will brain have to run
To determine how far Brian needs to run, we need to calculate his position at the time when Igor catches up with him.

We already know that it takes Igor approximately 1.51 seconds (t ≈ 1.51s) to catch up with Brian. Let's determine Brian's position at that time.

For Brian:
Initial velocity (v_i) = 0 m/s (since he starts accelerating from rest)
Acceleration (a_b) = 2.8 m/s^2 (positive because he is accelerating away)
Time (t) = 1.51s (approximately)

To find Brian's position after 1.51 seconds, we can use the formula: x_f = x_i + v_i*t + 0.5*a*t^2

Since Brian starts from position 0 (x_i = 0), and his initial velocity is also 0 (v_i = 0), we are left with:

x_f = 0 + 0 + 0.5*2.8*(1.51)^2

Simplifying this equation, we have:

x_f = 0 + 0 + 0.5*2.8*(2.2801)

x_f = 0 + 0 + 1.59608

x_f ≈ 1.6m

Therefore, Brian will have to run approximately 1.6 meters before Igor catches up with him.