a ford explorer traveled 100 miles the next day for 5 hours. What was the average speed of this vehicle?

Use the work-energy theorem to determine the force required to stop a 1000 kg car moving at a speed of 20.0 m/s if there is a di

Vlad1618 [11]

Answer:

4.44 kN in the opposite direction of acceleration.

Explanation:

Given that, the initial speed of the car is, $u=20m/s$

And the mass of the car is, $m=1000 kg$

The total distance covered by the car before stop, $s=45m$

And the final speed of the car is, $u=0m/s$

Now initial kinetic energy is,

$KE_{i}=\frac{1}{2}mu^{2}$

Substitute the value of u and m in the above equation, we get

$KE_{i}=\frac{1}{2}(1000kg)\times (20)^{2}\\KE_{i}=20000J$

Now final kinetic energy is,

$KE_{f}=\frac{1}{2}mv^{2}$

Substitute the value of v and m in the above equation, we get

$KE_{f}=\frac{1}{2}(1000kg)\times (0)^{2}\\KE_{i}=0J$

Now applying work energy theorem.

Work done= change in kinetic energy

Therefore,

$F.S=KE_{f}-KE_{i}\\F\times 45=(0-200000)J\\F=\frac{-200000J}{45}\\ F=-4444.44N\\F=-4.44kN$

Here, the force is negative because the force and acceleration in the opposite direction.

6 0

3 years ago

PLZ HELP!!! Detailed PLZ!

Korolek [52]

Answer:

Potential Energy = 294J, Kinetic Engergy = 48.02J

Explanation:

We have these formulas:

Potential Energy = mass * gravitational force * height (m) = 1 * 9.8 * 30 = 294(J)

Kinetic Energy = 1/2 * mass * velocity^2 = 1/2 * 1 * 9.8^2 = 48.02 (J)

As the rock falling at an acceleration of 9.8m/s^2 which means for each second, the rock increases 9.8m/s. I think we are missing time to find the instantaneous velocity, the formula is (initial displacement - final displacement)/ (initial time - final time) which will directly give the final answer for you.

5 0

4 years ago

A go-kart and rider have a mass of 14 kg. If the cart accelerates at 6 m/s² during a 40 m sprint in 100 seconds, how much power

Nutka1998 [239]

Answer:

P=33.6 \ W

Explanation:

Mechanical Work and Power

Work is the amount of energy transferred by a force. It's a scalar quantity, with SI units of joules.

Being $\vec F$ the force vector and $\vec s$ the displacement vector, the work is calculated as:

$W=\vec F\cdot \vec s$

If both the force and displacement are parallel, then we can use the equivalent scalar formula:

$W=F.s$

Mechanical Power is the amount of energy transferred or converted per unit of time. The SI unit of power is the watt, equal to one joule per second.

The power can be calculated as:

$\displaystyle P=\frac {W}{t}$

Where W is the work and t is the time.

If an object of mass m has an acceleration a, the net force is:

F=m.a

The go-kart and rider have a mass of m=14 kg and accelerate at $6 m/s^2$ , thus the net force applied is:

$F=14\cdot 6 = 84\ N$

The work done by the cart when traveling d= 40 m is:

$W=84\cdot 40$

$W=3,360\ J$

Finally, the power for t= 100 seconds is:

$\displaystyle P=\frac {3,360}{100}$

P=33.6 \ W

5 0

3 years ago

In one contest at the county fair, a spring-loaded plunger launches a ball at a speed of 3.2m/s from one corner of a smooth, fla

lara31 [8.8K]

Answer:

Explanation:

Given

Speed of ball $u=3.2\ m/s$

Plane is inclined at an angle $20^{\circ}$

To win the Game we need to hit the target at $x=2.4\ m$ away

Launch angle of ball $\theta$

Motion of ball can be considered in two planes i.e. Vertical to the plane and horizontal to the plane

So Net acceleration in vertical plane is $g\sin 20$

Range of Projectile is given by

$R=\frac{u^2\sin 2\theta }{g}$

for $R=2.4\ m$

$2.4=\frac{3.2^2\times sin 2\theta }{g\sin 20}$

$\sin 2\theta =\frac{2.4\times 9.8\times \sin 20}{3.2^2}$

$\sin 2\theta =0.7855$

$2\theta =51.77$

$\theta =25.88^{\circ}$

so ball must be launched at an angle of $25.88^{\circ}$

4 0

3 years ago

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

aksik [14]

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J