12)It is summertime and two boys cannot wait for winter. One boy exerts a 70N horizontal force as he pushes his 58 kg friend standing on a snowboard across a cement sidewalk at a constant speed. What is the coefficient of kinetic between the sidewalk and the snowboard? Ignore air resistance and the weight of the snowboard.

.12

13)The sign of the x component of a vector in the 3rd quadrant would be?

negative

14)The cable of the elevator you are riding in breaks and the elevator begins to freefall at terminal velocity to the ground. Why would jumping up right before impact still not help you survive?

b/c your overall inertia is down

12) 0.123

13) yes

14) Because you still must undergo deceleration to zero velocity in a very short time. Forces exerted upon you would be about the same but slightly less.

14) my choices are:

A)what I wrote
B)b/c you would be accelerating up
C)b/c you are weightless
D)it would help you survive

if the answer is in what you said, I don't get it

Because your overall inertia is down, or a 4 number 14

12) To find the coefficient of kinetic friction between the sidewalk and the snowboard, we need to use the equation for friction force. The friction force is given by the formula: Friction force = coefficient of kinetic friction * normal force. In this case, the normal force is equal to the weight of the person on the snowboard, which is given by the equation: normal force = mass * gravitational acceleration. Plugging in the values, we have: normal force = 58 kg * 9.8 m/s^2 = 568.4 N.

Since the snowboard is moving at a constant speed, the friction force must be equal in magnitude and opposite in direction to the horizontal force exerted by the boy. Therefore, friction force = 70 N.

Now we can plug the values into the formula and solve for the coefficient of kinetic friction:
70 N = coefficient of kinetic friction * 568.4 N
coefficient of kinetic friction = 70 N / 568.4 N ≈ 0.123 or 0.12 (rounded to two decimal places).

So, the coefficient of kinetic friction between the sidewalk and the snowboard is approximately 0.12.

13) The 3rd quadrant is characterized by negative values for both x and y coordinates. In the Cartesian coordinate system, the x component of a vector is positive if it lies along the positive x-axis, and negative if it lies along the negative x-axis. Therefore, in the 3rd quadrant, the x component of a vector would be negative.

14) When the elevator cable breaks and the elevator starts to freefall, the elevator and everything inside it, including you, are in a state of freefall. In freefall, both you and the elevator experience the same acceleration, which is equal to the acceleration due to gravity. Whether you jump or not, your overall inertia is still downward because gravity is acting on you.

Jumping up before impact would momentarily decrease your distance from the ground, but you would still be subject to the same acceleration due to gravity. The impact force when landing would be the same regardless of whether you jumped or not because it depends on the deceleration upon contact with the ground. However, jumping may cause additional risks such as hitting your head or limbs on the ceiling once the elevator starts moving upward again after you jump.

In summary, jumping up right before impact in a freefalling elevator will not help you survive because the overall inertia is still downward, and the impact force upon landing would be the same.