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3 years ago

Thomas needs to move an 80 kg rock, but cannot lift it. He decides to use a

Physics

1 answer:

ArbitrLikvidat [17]3 years ago

5 0

Answer:

Explanation:

The weight of the rock is W = mg = (80 kg) (10 m/s²) = 800 N.

The mechanical advantage is therefore 800 N / 200 N = 4.

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Atruck with a mass of 5280 Kg has an acceleration of 45 m/s/s what is the force acting on the truck?

horrorfan [7]

117.3 I think that’s it mb if that wrong

8 0

3 years ago

12. Suppose a person uses a mechanical iack to lift half the weight of a car with a

Likurg_2 [28]

a) The force that must be applied is 73.5 N

b) The actual efficiency is 82 %

Explanation:

Since the jack is 100% efficient, all the input work is converted into output work. So we can write:

$W_{in} = W_{out}\\F_{in} d_{in} = F_{out} d_{out}$

where:

$F_{in}$ is the input force applied on the jack

$d_{in}$ is the arm of the input force

$F_{out}$ is the output force applied on the jack

$d_{out}$ is the arm of the output force

Here we have:

$F_{out}=\frac{mg}{2}= \frac{(1200 kg)(9.8 m/s^2)}{2}=5880 N$ is the output force (half the weight of the car)

$d_{in} = 40.0 cm = 0.40 m$ is the arm of the input force

$d_{out} = 5.0 mm = 0.005 m$ is the arm of the output force

Solving for $F_{in}$ , we find the force that must be applied in input to lift the car:

$F_{in} = \frac{F_{out}d_{out}}{d_{in}}=\frac{(5880)(0.005)}{0.40}=73.5 N$

The efficiency of the jack is given by the ratio between the output work and the input work:

$\eta = \frac{W_{out}}{W_{in}}=\frac{F_{out}d_{out}}{F_{in}d_{in}}$

where we have:

$F_{out}=5880 N$ is the output force (half the weight of the car)

$d_{in} = 40.0 cm = 0.40 m$ is the arm of the input force

$d_{out} = 5.0 mm = 0.005 m$ is the arm of the output force

Here we are told that the input force this time is

$F_{in}=90.0N$

Substituting into the equation, we find the new efficiency of the jack:

$\eta = \frac{(5880)(0.005)}{(90.0)(0.40)}=0.82$

Which means an efficiency of 82%.

Learn more about levers:

brainly.com/question/5352966

#LearnwithBrainly

8 0

4 years ago

Mathphys please notice me

eimsori [14]

Answer:

24.2 s

29.2 m

Explanation:

First, convert each speed from km/h to m/s.

91.5 km/h = 25.42 m/s

77.5 km/h = 21.53 m/s

The speed of the cheetah relative to the gazelle is:

v = 25.42 m/s − 21.53 m/s

v = 3.89 m/s

So the time it takes for the cheetah to catch the gazelle is:

x = v t

94.2 m = (3.89 m/s) t

t = 24.2 s

If instead we want to find x so that t = 7.5 s, then:

x = v t

x = (3.89 m/s) (7.5 s)

x = 29.2 m

7 0

4 years ago

Read 2 more answers

you drive in a straight line at 20.0m/s for 10.0 min, then 30.0m/s for another 10.0 min. Find the average speed.

Juliette [100K]

Answer is 25 m/s.

Explanation;

Step 1 : Convert the units into same unit.

Here speeds are given in m/s while the time is in minutes. So, let's convert minutes into seconds.

1 min = 60 s

Then,

10 minutes = 10 x 60 s = 600 s

Step 2 : Find the total distance that you have travelled.

To find that you need to first find distances separately.

We know the formula, s = vt, where s is the distance, v is the speed or velocity and t is the time.

First you have travelled 10 minutes (600 s) at 20.0 m/s.

Then distance, s = 20.0 m/s x 600 s = 12 000 m

Secondly you have travelled again 10 minutes at 30.0 m/s

Then distance = 30.0 m/s x 600 s = 18 000 m

Then, the total distance = 12 000 m + 18 000 m = 30 000 m

Step 3 : Find the total time taken to travel.

Total time = 600 s + 600 s = 1200 s

Step 4 : Calculate the average speed.

Average speed = total distance / total time

= 30 000 m / 1200 s

= 25 m/s

6 0

3 years ago

Atoms form chemical bonds to satisfy the blank rule and become blank

Masja [62]

Answer:

Atoms form chemical bonds to satisfy the Octet rule and become Stable element.

Explanation:

Every atom desires to achieve total eight valence electron in their outermost shell to become stable. This rule is known as octet rule.
During the chemical reaction process, every element goes through the process of receiving or donating the element to complete the octet rule to become stable.

The electronic configuration of element having eight electrons in its valence shell is the noble gases.

5 0

3 years ago