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3 years ago

A 73.0 kg firefighter climbs a flight of stairs 9.0 m high. how much work is required? j

1 answer:

7 0

The strength of the fireman in vertical direction will be given by F = m * g. Then, the work done will be given by definition by W = F * d. Substituting the expression of the Force in that of the work, we have that the work will be W = m * g * d. Substituting the given values and assuming that g = 10m / s ^ 2, we have a total work of W = (73) * (10) * (9) = 6570 J

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In an attempt to impress its friends, an acrobatic beetle runs and jumps off the bottom step of a flight of stairs. The step is

Aleks04 [339]

Answer:

0.3677181864 m

Explanation:

u = Velocity = 1.5 m/s

$\theta$ = Angle = 20°

y = -20 cm

Velocity components

$u_x=ucos\theta\\\Rightarrow u_x=1.5cos20\\\Rightarrow u_x=1.40953\ m/s$

$u_y=usin\theta\\\Rightarrow u_y=1.5sin20\\\Rightarrow u_y=0.51303\ m/s$

Acceleration components

$a_x=0$

$a_y=-9.81\ m/s^2$

$y=u_yt+\dfrac{1}{2}a_yt^2\\\Rightarrow -0.2=0.51303\times t+\dfrac{1}{2}\times -9.81t^2\\\Rightarrow 4.905t^2-0.51303t-0.2=0$

$t=\frac{-\left(-0.51303\right)+\sqrt{\left(-0.51303\right)^2-4\cdot \:4.905\left(-0.2\right)}}{2\cdot \:4.905}, \frac{-\left(-0.51303\right)-\sqrt{\left(-0.51303\right)^2-4\cdot \:4.905\left(-0.2\right)}}{2\cdot \:4.905}\\\Rightarrow t=0.26088, -0.15629$

Time taken is 0.26088 seconds

$x=u_xt+\dfrac{1}{2}a_xt^2\\\Rightarrow x=1.40953\times 0.26088\\\Rightarrow x=0.3677181864\ m$

The distance the beetle travels on the ground is 0.3677181864 m

6 0

3 years ago

You are sharing a house with a few roommates. One of them plays on the basketball team, and is exactly 200 cm tall. The heights

Advocard [28]

Answer:

119 cm

Explanation:

Given heights : 200cm , 188 cm , 175 cm, 160 cm

since the eyes are at 95% level

95% of 200 cm = 190 cm

95% of 160 cm = 152 cm

hence the allowable height of mirror = 200 - ( 5 + 76 ) = 119 cm

and The mirror should be hung 75cm from the floor

8 0

3 years ago

Plz help I will give brainly to the correct answer

Tresset [83]

Answer:

D. x-rays

Explanation:

Lower frequency: Radio waves, microwaves and infrared have lower frequency than visible light. Shorter wavelength: Ultraviolet, x-rays and gamma rays have a shorter wavelength than visible light.

4 0

3 years ago

A toaster uses 6700 joules of energy in 45 seconds to toast to a piece of bread what is power of the oven

just olya [345]

P= w/t and W= Work
In this case, W= 6,700j, and T= 45 seconds
Power is the ratio of work per unit time. When you perform a work in a given span of time, the ratio of work performed with respect to time is Called Power.
si unit for Power is Watt (W)
so, P= 6,700/45
P= 148
Final answer is P=148

8 0

3 years ago

16)

VMariaS [17]

Answer:

a.proton, proton

hope this helped :) have a goodday

6 0

4 years ago