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Sergeeva-Olga [200]

3 years ago

14

If you want to lift a 5-kg box to a height of 2 meters, how much work must be

1 answer:

BlackZzzverrR [31]3 years ago

5 0

Answer:100joules

Explanation:

Mass(m)=5kg

Acceleration due to gravity(g)=10m/s^2

Height(h)=2 meters

Work=m x g x h

Work=5 x 10 x 2

Work=100joules

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To meet a U.S. Postal Service requirement, employees' footwear must have a coefficient of static friction of 0.5 or more on a sp

motikmotik

Answer:

0.79 s

Explanation:

We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:

$\sum F_x:f_{max}=ma_x\\\sum F_y:N-mg=0$

The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that $f_{max}=\mu N$

Now, we find the acceleration:

$\mu N=ma_x\\\mu mg=ma_x\\a_x=\mu g\\a_x=0.83(9.8\frac{m}{s^2})\\a_x=8.134\frac{m}{s^2}$

Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:

$x=v_0t+\frac{1}{2}a_xt^2\\2x=a_xt^2\\t=\sqrt{\frac{2x}{a}}\\t=\sqrt{\frac{2(3.2m)}{8.134\frac{m}{s^2}}}\\t=0.79 s$

8 0

3 years ago

Consider a small car of mass 1200 kg and a large sport utility vehicle (SUV) of mass 4000 kg. The SUV is traveling at the speed

Karolina [17]

Answer:

63.9 m/s

Explanation:

Parameters given:

Mass of small car, m = 1200 kg

Mass of SUV, M = 4000 kg

Speed of SUV, V = 35 m/s

Their kinetic energy of the small car is equal to the kinetic energy of the SUV, hence:

0.5 * m * v² = 0.5 * M * V²

=> 0.5 * 1200 * v² = 0.5 * 4000 * 35²

600 * v² = 2450000

v² = 2450000/600

v² = 4083.3

=> v = 63.9 m/s

The speed of the small car is 63.9 m/s.

6 0

3 years ago

A kicker kicks a ball off the ground at 29.5 mi/hr and at 42.5 degrees.

deff fn [24]

Answer:

20.3m

Explanation:

the formula used was

s=(u^2sin^2∆)÷2g

4 0

3 years ago

An automobile with a tangential speed of 54.1 km/h follows a circular road that has a radius of 41.6 m. The automobile has a mas

Viefleur [7K]

1) Available force of friction: 6174 N

2) No

Explanation:

1)

The magnitude of the frictional force between the car's tires and the pavement of the road is given by

$F_f=\mu mg$

where

$\mu$ is the coefficient of friction

m is the mass of the car

g is the acceleration of gravity

For the car in this problem, we have:

$\mu=0.500$ (coefficient of friction)

m = 1260 kg (mass of the car)

$g=9.8 m/s^2$

Therefore, the force of friction is

$F_f=(0.500)(1260)(9.8)=6174 N$

2)

In order to mantain the car in circular motion, the force of friction must be at least equal to the centripetal force.

The centripetal force is given by

$F=m\frac{v^2}{r}$

where

m is the mass of the car

v is the tangential speed

r is the radius of the curve

In this problem, we have

m = 1260 kg

$v=54.1 km/h =15.0 m/s$ is the tangential speed

r = 41.6 m is the radius of the curve

Therefore, the centripetal force is

$F=(1260)\frac{15.0^2}{41.6}=6814 N$

Therefore, the force of friction is not enough to keep the car in the curve, since $F_f$

4 0

3 years ago

Fjcivudjxivjsjcjfjs sufi sucks djviw dubai xocovnw divoe

sleet_krkn [62]

Explanation:

gajqbq haiwjwj jajwbw

thanks for the point

8 0

3 years ago

Read 2 more answers