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2 years ago

1200 kg car is being driven down a road. If it has 101 kJ of kinetic energy, what is its speed?

Physics

1 answer:

vova2212 [387]2 years ago

5 0

Kinetic Energy = (1/2) (mass) (speed)²

101,000 J = (1/2) (1200 kg) (speed)²

Speed² = 101,000 J / 600 kg

Speed² = 168 and 1/3 m²/s²

Speed = √(168 and 1/3 m²/s²)

<em>Speed = 12.97 m/s</em>

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A 0.15 kg baseball is hit by a baseball bat. Right before it is hit, the ball’s speed is 30 m/s, and right after it is hit, the

Roman55 [17]

Answer:

Impulse will be 12 kgm/sec

So option (b) will be correct option

Explanation:

We have given mass of the baseball m = 0.15 kg

Ball speed before hit $v_1=30m/sec$

Ball speed after hitting $v_2=-50m/sec$ ( negative direction due to opposite direction )

We have to find the impulse

We know that impulse is equal; to the change in momentum

So change in momentum = $m(v_1-v_2)=0.15(30-(-50))=0.15\times 80=12kgm/sec$

So option (b) will be correct option

5 0

2 years ago

The density is 1.5 g/cm^3. the mass is 1500. what is the volume

Naddik [55]

The density of an object can be calculated using the formula Density = Mass/Volume. In this case however we are searching for the volume and must rearrange the formula so that we are solving for the volume. If you multiply both sides by volume and then divide both sides by mass you end up with the equation Volume = Mass/Density.

Volume = 1500g/1.5g/cm^3
Volume = 1000 cm^3

8 0

3 years ago

A small sculpture made of brass (rho brass = 8470 kg/m 3 ) is believed to have a secret central cavity. The weight of the sculpt

GaryK [48]

Answer:

Volume of secret cavity = 4 x 10⁻⁶m³

Explanation:

The weight of the sculpture in air is 15.76 N

Mass of the sculpture = 1.61 kg

Mass = Volume x Density

1.61 = V x 8470

Volume of brass =1.90 x 10⁻⁴ m³

When it is submerged in water, the weight is 13.86 N.

That is

Weight of sculpture - Weight of water displaced = 13.86 N

15.76 - Weight of water displaced = 13.86

Weight of water displaced = 1.9 N

Mass of water displaced = 0.194 kg

Mass = Volume x Density

0.194 = V x 1000

Volume of water displaced =1.94 x 10⁻⁴ m³

Volume of secret cavity = Volume of water displaced - Volume of brass material

Volume of secret cavity = 1.94 x 10⁻⁴-1.94 x 10⁻⁴ = 0.04x 10⁻⁴ = 4 x 10⁻⁶m³

7 0

3 years ago

You have a grindstone (a disk) that is 90.0 kg, has a 0.340-m radius, and is turning at 90.0 rpm, and you press a steel axe agai

QveST [7]

Answer:

Explanation:

Given mass of grindstone $m=90\ kg$

radius of stone $r=0.34\ m$

angular speed of disc $\omega =90\ rpm$

Steel Axle applying a force of $F=20\ N$

coefficient of kinetic friction $\mu =0.2$

Frictional Torque applied by steel is given by

$\tau=r\times f_r$

$\tau =r\times \mu F$

where $f_r$ =frictional force

$\tau =r\times \mu \times F$

$\tau =0.34\times 0.2\times 20$

$\tau =1.36\ N-m$

Torque is also given by

$\tau =I\cdot \alpha$

where $\alpha$ =angular acceleration

I=moment of Inertia

$\tau =0.5Mr^2\times \alpha$

$0.5Mr^2\times \alpha =1.36\ N-m$

$0.5\times 90\times 0.34^2\times \alpha =1.36$

$\alpha =0.261\ rad/s^2$

3 0

3 years ago

When voltage sources are connected in series, the total voltage is equal to the algebraic sum of the individual voltages?

Vesnalui [34]

According to the third rule of series circuit, the total voltage is equal to the sum of individual voltages. These proves that the statement above "<span>When voltage sources are connected in series, the total voltage is equal to the algebraic sum of the individual voltages?" is TRUE.</span>

7 0

3 years ago