Sparrow mass $50\,\text{g}$ flies at altitude $20\,\text{m}$ at speed $12\,\text{m/s}$. Determine the momentum and total mechanical energy of the sparrow.

p = 0{,}6\,\tfrac{\text{kg}\cdot\text{m}}{\text{s}}; E_0 = 13{,}6\,\text{J}

Body mass $400\,\text{g}$ begins to move under the influence of force $1{,}2\,\text{N}$. What speed will it acquire in $6\,\text{s}$?

v = 18\,\tfrac{\text{m}}{\text{s}}

Kite mass $1{,}5\,\text{kg}$ flies at speed $6\,\text{m/s}$. Its total mechanical energy is $327\,\text{Dzh}$. Determine momentum, kinetic energy and altitude.

p = 9\,\tfrac{\text{kg}\cdot\text{m}}{\text{s}}; E_{\text{k}} = 27\,\text{J}; h = 20\,\text{m}

A boy carries a sled, applying it to the rope at an angle $30^{\circ}$ force $8\,\text{N}$. For $15\,\text{s}$ the sled passed $30\,\text{m}$. Define work and power.

A = 208\,\text{J}; N = 13{,}9\,\text{W}

Bullet mass $10\,\text{g}$ has kinetic energy $3200\,\text{Dzh}$. Determine the recoil velocity of a rifle with a mass $4\,\text{kg}$ and the work of powder gases.

v_2 = 2\,\tfrac{\text{m}}{\text{s}}; A = 3208\,\text{J}

Car weight $20\,\text{t}$ moves at speed $0{,}5\,\text{m/s}$ towards the car with a mass $30\,\text{t}$ at speed $0{,}4\,\text{m/s}$. Determine the total velocity after the inelastic collision and the amount of heat generated by the collision.

v_x = -0{,}04\,\tfrac{\text{m}}{\text{s}}; Q = 4860\,\text{J}

Vehicle weight $800\,\text{kg}$ moves at speed $54\,\text{km/ch}$. The friction coefficient is equal to $0{,}08$. How much power does the engine develop and how much work does it do per minute with uniform motion?

N = 9600\,\text{W}; A = 576\,000\,\text{J}

In a spring gun, the spring is compressed by $5\,\text{sm}$. Determine the spring stiffness if the bullet weighs $8\,\text{g}$ flies out at speed $5\,\text{m/s}$.

k = 80\,\tfrac{\text{N}}{\text{m}}

The recoil speed of the gun barrel when fired is equal to $20\,\text{m/s}$. Barrel weight $800\,\text{kg}$, projectile mass $16\,\text{kg}$. Determine the speed of the projectile.

v_2 = 1000\,\tfrac{\text{m}}{\text{s}}

10TH GRADE PRACTICE

Physics Problems: Conservation laws, Grade 10

Impulse, work, power and energy.

17 problems across 2 sub-topics

Practise in the interactive mode

Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.

Problem statements

The answer options are there to check against, and the walkthrough opens under each problem.

17 problems

Position in this set: 1 from 17

Problem #4

Conservation laws: energy, work and power

Sparrow mass flies at altitude at speed . Determine the momentum and total mechanical energy of the sparrow.

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Given

Find

Total mechanical energy consists of kinetic and potential.

Answer

Position in this set: 2 from 17

Problem #54

Conservation laws: energy, work and power

Body mass begins to move under the influence of force . What speed will it acquire in ?

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Given

Find

Through the force impulse it is shorter: Ft = mv, whence v = Ft/m.

Answer

Position in this set: 3 from 17

Problem #55

Conservation laws: energy, work and power

Kite mass flies at speed . Its total mechanical energy is . Determine momentum, kinetic energy and altitude.

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Given

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Answer

Position in this set: 4 from 17

Problem #56

Conservation laws: energy, work and power

boy mass rises to the fifth floor . Floor height . How much power does it develop?

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Given

Find

From the first floor to the fifth there are four flights, not five.

Answer

Position in this set: 5 from 17

Problem #57

Conservation Laws: Momentum

Material point with mass moves in a circle with radius with frequency . Define impulse. What is the change in momentum over a period, half and quarter period?

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Position in this set: 6 from 17

Problem #58

Conservation Laws: Momentum

Bullet mass at speed punches a ball with mass and flies out at speed . How high will the ball rise?

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Given

Find

The law of conservation of momentum when breaking through a ball.

Answer

Position in this set: 7 from 17

Problem #59

Conservation laws: energy, work and power

A boy carries a sled, applying it to the rope at an angle force . For the sled passed . Define work and power.

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Given

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Work is performed only by the component of the force along the displacement.

Answer

Position in this set: 8 from 17

Problem #60

Conservation laws: energy, work and power

Under force body mass rose to heights from a state of rest. Determine the kinetic energy at this height.

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Given

Find

The work of force goes both for lifting and acceleration.

Answer

Position in this set: 9 from 17

Problem #61

Conservation laws: energy, work and power

Body mass falls from a height . Determine the kinetic energy at altitude above the Earth.

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Given

Find

The total mechanical energy is conserved.

Answer

Position in this set: 10 from 17

Problem #63

Conservation Laws: Momentum

Icebreaker mass collided with a stationary iceberg at speed . After the collision, the speed of the icebreaker became . Determine the mass of the iceberg, assuming joint motion.

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Given

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The collision is inelastic: the bodies then move together.

Answer

Position in this set: 11 from 17

Problem #64

Conservation laws: energy, work and power

Bullet mass has kinetic energy . Determine the recoil velocity of a rifle with a mass and the work of powder gases.

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Given

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Answer

Position in this set: 12 from 17

Problem #65

Conservation laws: energy, work and power

Car weight moves at speed towards the car with a mass at speed . Determine the total velocity after the inelastic collision and the amount of heat generated by the collision.

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Given

Find

The cars are moving towards each other, so the impulses are subtracted.
A minus sign means that the coupler will move towards the second car.

Answer

Position in this set: 13 from 17

Problem #66

Conservation laws: energy, work and power

Vehicle weight moves at speed . The friction coefficient is equal to . How much power does the engine develop and how much work does it do per minute with uniform motion?

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Given

Find

At constant speed, the thrust is equal to the friction force.

Answer

Position in this set: 14 from 17

Problem #67

Conservation laws: energy, work and power

In a spring gun, the spring is compressed by . Determine the spring stiffness if the bullet weighs flies out at speed .

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Given

Find

The energy of the compressed spring is completely converted into the kinetic energy of the bullet.

Answer

Position in this set: 15 from 17

Problem #68

Conservation laws: energy, work and power

Arrow mass launched vertically upward at a speed . Determine its kinetic energy at height .

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Given

Find

Part of the initial kinetic energy turned into potential.

Answer

Position in this set: 16 from 17

Problem #69

Conservation laws: energy, work and power

The recoil speed of the gun barrel when fired is equal to . Barrel weight , projectile mass . Determine the speed of the projectile.

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Given

Find

Law of conservation of momentum: the total momentum before and after is zero.

Answer

Position in this set: 17 from 17

Problem #70

Conservation laws: energy, work and power

Body mass when falling to Earth it has kinetic energy . From what height did it fall?

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Given

Find

All kinetic energy turns into potential energy.

Answer

The theory behind these problems

Work through the topic if a problem will not give in.

Free fall and circular motionFall without resistance and kinematics of uniform rotation.Momentum and its conservationBody impulse, force impulse and closed system.Work, power and energyWork of forces, types of mechanical energy and the law of conservation.

Formulas by topic

Look up symbols and units of measurement in the reference.

Body impulsep · kg m/s PowerP, N · W PeriodT · with WorkA · J Angular velocityω · rad/s Frequencyν · Hz EnergyE, W · J