2nd question!!!!!!!!!!!!!!!!!!!

A 110 kg quarterback is running the ball downfield at 4.5 m/s in the positive direction when he is tackled head-on by a 150 kg l

melisa1 [442]

Answer:

$v_f=-0.29\frac{m}{s}$

Explanation:

The principle of conservation of momentum, states that if the sum of the forces acting on a system is null, the initial total momentum of the system before a collision equals the final total momentum of the system after the collision. The collision is completely inelastic, which means that the players remain stick to each other after the collision:

$p_i=p_f\\m_1v_1+m_2v_2=(m_1+m_2)v_f\\v_f=\frac{m_1v_1+m_2v_2}{(m_1+m_2)}\\\\v_f=\frac{(110kg)4.5\frac{m}{s}+150kg(-3.8\frac{m}{s})}{(110kg+150kg)}\\v_f=-0.29\frac{m}{s}$

5 0

3 years ago

If a green light shines on a red toy, the toy will look:

disa [49]

Not 100% sire but I think it'd be Yellow since we see red and green light together as Yellow

4 0

3 years ago

contractor will use a package emulsion having a specific gravity of 1.25 and relative bulk strength of 130 to open an excavation

tester [92]

Answer:

The burden distance is 7 ft

Solution:

As per the question:

Specific gravity of package emulsion, $SG_{E} = 1.25$

Specific gravity of diabase rock, $SG_{R} = 2.76$

Diameter of the packaged sticks, d = 3 in

Now,

To calculate the first trail shot burden distance, B:

$B = [\frac{2SG_{E}}{SG_{R}} + 1.5]\times d$

$B = [\frac{2\times 1.25}{2.76} + 1.5]\times 3 = 7.22$

B = 7 ft

5 0

3 years ago

A fireman of 80 kg slides down a pole.When he reaches the bottom, 4.2 m below his starting point, his speed is 2.2 m/s . By how

levacccp [35]

Answer:

3099 J

Explanation:

The increase in thermal energy corresponds to the mechanical energy lost in the process.

The mechanical energy is given by the sum of gravitational potential energy and kinetic energy of the fireman:

$E=K+U$

At the top of the pole, the fireman has no kinetic energy, so all his mechanical energy is just potential energy:

$E=U=mgh=(80 kg)(9.8 m/s^2)(4.2 m)=3293 J$

When the fireman reaches the bottom, he has no gravitational potential energy, so his mechanical energy is just given by his kinetic energy:

$E=K=\frac{1}{2}mv^2=\frac{1}{2}(80 kg)(2.2 m/s)^2=194 J$

So, the loss in mechanical energy was

$\Delta E=3293 J-194 J=3099 J$

and this corresponds to the increase in thermal energy.

7 0

3 years ago

The Fitness Log is:

Molodets [167]

Answer:

D. A record of all the physical activity you complete in one week.

Explanation:

A "Fitness Log" allows you to keep track of your workout or exercise. Therefore, it is a record of the different workout you've managed to complete within a time frame. It gives you several information such as the type of workout you've completed, its duration and the time of the day it was performed. This makes a person motivated to exercise because he can see his progress. He may also include his mood before and after workout in order to become more mindful in exercising and many other things.

8 0

3 years ago