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sergiy2304 [10]
3 years ago
9

A bicyclist is finishing his repair of a flat tire when a friend rides by with a constant speed of 3.6 m/s . Two seconds later t

he bicyclist hops on his bike and accelerates at 2.0 m/s2 until he catches his friend. A.) How much time does it take until he catches his friend (after his friend passes him)? t=___s B.) How far has he traveled in this time? x= ____ m
C.) What is his speed when he catches up? v=____ m/s
Physics
1 answer:
dybincka [34]3 years ago
8 0

Answer:

A) t = 7.0 s    

B) x = 25 m  

C) v = 10 m/s

Explanation:

The equations for the position and velocity of an object traveling in a straight line is given by the following expressions:

x = x0 + v0 · t + 1/2 · a · t²

v = v0 + a · t

Where:

x = position at time t

x0 = initial position

v0 = initial velocity

t = time

a = acceleration

v = velocity at time t

A)When both friends meet, their position is the same:

x bicyclist = x friend

x0 + v0 · t + 1/2 · a · t² = x0 + v · t

If we place the center of the frame of reference at the point when the bicyclist starts following his friend, the initial position of the bicyclist will be 0, and the initial position of the friend will be his position after 2 s:

Position of the friend after 2 s:

x = v · t

x = 3.6 m/s · 2 s = 7.2 m

Then:

1/2 · a · t² = x0 + v · t       v0 of the bicyclist is 0 because he starts from rest.

1/2 · 2.0 m/s² · t² = 7.2 m + 3.6 m/s · t

1  m/s² · t² - 3.6 m/s · t - 7.2 m = 0

Solving the quadratic equation:

t = 5.0 s

It takes the bicyclist (5.0 s + 2.0 s) 7.0 s to catch his friend after he passes him.

B) Using the equation for the position, we can calculate the traveled distance. We can use the equation for the position of the friend, who traveled over 7.0 s.

x = v · t

x = 3.6 m/s · 7.0 s = 25 m

(we would have obtained the same result if we would have used the equation for the position of the bicyclist)

C) Using the equation of velocity:

v = a · t

v = 2.0 m/s² · 5.0 s = 10 m/s

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I WILL MARK YOU THE BRAINLIEST
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Explanation:

700N right

to get the net force

you gotta let one direction be the negative ( the smaller force)

so the total force towards the left is 100N ( 60 + 40= 100)

which is smaller than the right force which is 800 N so you let 100 N be negative

so without even calculating , you can know that it will be moving towards the right because right force > left force

your add both forces ( remember 100 N is negative)

so 800N + ( - 100N)

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hope this helps

this is just one method that helped me understand

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