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vampirchik [111]

3 years ago

15

A boy is exerting a force of 70 N at a 50-degree angle on a lawn mower. He is accelerating at 1.8 m/s2. Round the answers to the

nearest whole number.
What is the mass of the lawn mower?
kg
What is the normal force exerted on the lawn mower?
N

1 answer:

charle [14.2K]3 years ago

8 0

Answer:

are you in middle school

Explanation:

need more evendice

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Concrete colums are constructed with reinforcing steel in them to make them stronger and more ductile. The reinforcing bars are

Sergio039 [100]

Answer:

$21678.47223\ lbf-in^2$

$383.1109\ lbf-in^2$

Explanation:

d = Diameter of column = 0.5 inch

$A_c$ = Area of concrete = $119.4\ in^2$

The strain in the system is conserved

$\dfrac{F_sL}{A_sE_s}=\dfrac{F_cL}{A_cE_c}\\\Rightarrow F_c=\dfrac{F_sA_cE_c}{A_sE_s}\\\Rightarrow F_c=\dfrac{F_s \times 119.4\times 4.1\times 10^6}{8\times \dfrac{\pi \dfrac{1}{2^2}}{4}\times 29\times 10^6}\\\Rightarrow F_c=10.74658F_s$

Now

$F_c+F_s=50000\\\Rightarrow 10.74658F_s+F_s=50000\\\Rightarrow F_s=\dfrac{50000}{11.74658}\\\Rightarrow F_s=4256.55807\ lbf$

$F_c=10.74658F_s\\\Rightarrow F_c=10.74658\times 4256.55807\\\Rightarrow F_c=45743.44182\ lbf$

Stress is given by

$\sigma_s=\dfrac{4256.55807}{\pi \dfrac{1}{2^2}}{4}\\\Rightarrow \sigma_s=21678.47223\ lbf-in^2$

The stress in the steel is $21678.47223\ lbf-in^2$

$\sigma_c=\dfrac{45743.44182}{119.4}\\\Rightarrow \sigma_s=383.1109\ lbf-in^2$

The stress in the steel is $383.1109\ lbf-in^2$

4 0

3 years ago

Contrast elastic potential energy and chemical potential energy

tatuchka [14]

Chemical Potential Energy is released when chemical bonds between atoms are broken (like covalent and ionic) and is released mainly as thermal
<span>Elastic Potential is released when the molecules in the material are allowed to go back to there original form, and is released mainly as kinetic</span>

3 0

3 years ago

An electric drill transfers 200 J of energy into a useful kinetic energy store. It also transfers 44 J of energy by sound and 48

kramer

Answer:

Er = 108 [J]

Explanation:

To solve this problem we must understand that the total energy is 200 [J]. Of this energy 44 [J] are lost in sound and 48 [J] are lost in heat. In such a way that these energy values must be subtracted from the total of the kinetic energy.

200 - 44 - 48 = Er

Where:

Er = remaining energy [J]

Er = 108 [J]

3 0

3 years ago

Why is it difficult to cut using a pair if of scissors with blunt blades

zlopas [31]

Its not sharp enough to cut through whatever your trying to cut. Imagine trying to cut paper with your index finger and your middle finger. Doesn't work does it?

8 0

3 years ago

Suppose a truck has a momentum of 40,120 kg • and a mass of 1,180 kg. What is the truck’s velocity?

gladu [14]

<u>Answer:</u>

The velocity of the truck is 34 m/s.

<u>Explanation:</u>

The momentum (p) of an object is the product of its mass (m) and its velocity (v) which can be written as:

<em>p = mv</em>

Here in this problem, we are given a truck which has a momentum of 40120 kg and a mass of 1180 kg and we are to find its velocity.

So substituting the given values in the above formula to find the velocity of the truck.

Truck's velocity = $\frac{40120}{1180}$ = 34 m/s.

3 0

3 years ago