Which of the following is not a benefit of improved cardio-respiratory fitness?

Please can someone solve this physics question with a good explenation.

zimovet [89]

Answer:

The coefficient of dynamic friction is 0.025.

Explanation:

Given:

Initial speed after the push is 'v' as seen in the graph.

Final speed of the stone is 0 m/s as it comes to rest.

Total distance traveled is, $D=29.8\ m$

Total time taken is, $t_{total}=17.5\ s$

Time interval for deceleration is 3.5 to 17.5 s which is for 14 s.

Now, average speed of the stone is given as:

$v_{avg}=\frac{D}{t_{total}}=\frac{29.8}{17.5}=1.703\ m/s$

Now, we know that, average speed can also be expressed as:

$v_{avg}=\frac{v_i+v_f}{2}\\1.703=\frac{v+0}{2}\\v=2\times 1.703=3.41\ m/s$

Now, from the graph, the vertical height of the triangles is, $v=3.41\ m/s$

The deceleration is given as the slope of the line from time 3.5 s to 17.5 s.

Therefore, deceleration is:

$a=\frac{\textrm{Vertical height}}{\textrm{Time interval}}\\a=\frac{v-0}{17.5-3.5}\\a=\frac{3.41}{14}=0.244\ m/s^2$

Frictional force is the net force acting on the stone. Frictional force is given as:

$f=\mu_dN\\Where, \mu_d\rightarrow \textrm{coefficient of dynamic friction}\\N\rightarrow \textrm{Normal force}\\N=mg\\\therefore f=\mu_dmg$

Now, from Newton's second law, net force is equal to the product of mass and acceleration.

Therefore,

$\mu_dmg=ma\\\mu_d=\frac{a}{g}$

Plug in 0.244 for 'a' and 9.8 for 'g'. This gives,

$\mu_d=\frac{a}{g}=\frac{0.244}{9.8}=0.025$

Therefore, the coefficient of dynamic friction is 0.025.

3 0

3 years ago

1. A jogger jogs 25 m East, stops to rest, then continues for 10 more meters

Komok [63]

Answer:

35m

Explanation:

25m + 10m = 35m east.

*(adding since it's in the same direction)

8 0

3 years ago

A train moving at a constant speed of 50.0 km/h moves east for 45.0 min, then in a direction 45.0° east of due north for 10.0 mi

Yuki888 [10]

Answer:

3.47km/h with a direction of 67.8 degrees north of west.

Explanation:

First we need to calculate the displacement on the X axis, so:

$d_{x1}=50.0km/h*45min(\frac{1h}{60min})=37.5km\\d_{x2}=50.0km/h*10min(\frac{1h}{60min})*cos(45^o)=5.90km\\d_{x1}=-50.0km/h*55.0min(\frac{1h}{60min})=45.8km\\D_x=37.5+5.90-45.8=-2.4km$

then on the Y axis:

$D_y=50.0km/h*10min(\frac{1h}{60min})*sin(45^o)=5.90km$

The magnitud of the displacement is given by:

$D=\sqrt{D_x^2+D_y^2} \\D=6.37km$

and the angle:

$\alpha =arctg(\frac{5.90}{2.41})=67.8^o$

that is 67.8 degrees north of west.

$v=\frac{D}{t}\\v=\frac{6.37km}{110min*\frac{1h}{60min}}\\v=3.47km/h$

8 0

4 years ago

Which statement is true regarding a chemical reaction?

alina1380 [7]

Answer:

B) The total number of atoms does not change, so mass is conserved in the reaction.

Explanation:

According to the <u><em>Law of Conservation of Mass</em></u>, no matter can ever be created or destroyed. The number of atoms does not change, thus the mass does not change.

8 0

3 years ago

Read 2 more answers

What injuries could occur due to incorrect movement and handling of equipment with any sport or activity? (Select ALL that apply

NeTakaya

Sprains/Strains, tears to muscles, tendons ligaments, not hypothermia bc thats when you get really cold and not dehydrated

4 0

4 years ago