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10TH GRADE PRACTICE

Physics Problems: Conservation laws, Grade 10

Impulse, work, power and energy.

17 problems2 subtopics
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CONDITIONS

Problems

17
№ 4

Problem 4

Conservation laws: energy, work and power

A sparrow with a mass of 50 g50\,\text{g} flies at a height of 20 m20\,\text{m} with a speed of 12 m/s12\,\text{m/s}. Determine the momentum and total mechanical energy of the sparrow.

  1. (1,2 kg⋅m/s; 27,2 Dzh)\left(1{,}2\,\text{kg}\cdot\text{m/s};\ 27{,}2\,\text{Dzh}\right)
  2. (6 kg⋅m/s; 136 Dzh)\left(6\,\text{kg}\cdot\text{m/s};\ 136\,\text{Dzh}\right)
  3. (0,6 kg⋅m/s; 13,6 Dzh)\left(0{,}6\,\text{kg}\cdot\text{m/s};\ 13{,}6\,\text{Dzh}\right)
  4. (0,3 kg⋅m/s; 6,8 Dzh)\left(0{,}3\,\text{kg}\cdot\text{m/s};\ 6{,}8\,\text{Dzh}\right)
№ 54

Problem 54

Conservation laws: energy, work and power

A body of mass 400 g400\,\text{g} begins to move under the influence of a force 1,2 N1{,}2\,\text{N}. What speed will it acquire in 6 s6\,\text{s}?

  1. 18 m/s18\,\text{m/s}
  2. 9 m/s9\,\text{m/s}
  3. 36 m/s36\,\text{m/s}
  4. 180 m/s180\,\text{m/s}
№ 55

Problem 55

Conservation laws: energy, work and power

A kite with a mass of 1,5 kg1{,}5\,\text{kg} flies at a speed of 6 m/s6\,\text{m/s}. Its total mechanical energy is 327 J327\,\text{J}. Determine momentum, kinetic energy and altitude.

  1. (90 kg⋅m/s; 270 Dzh; 200 m)\left(90\,\text{kg}\cdot\text{m/s};\ 270\,\text{Dzh};\ 200\,\text{m}\right)
  2. (9 kg⋅m/s; 27 Dzh; 20 m)\left(9\,\text{kg}\cdot\text{m/s};\ 27\,\text{Dzh};\ 20\,\text{m}\right)
  3. (4,5 kg⋅m/s; 13,5 Dzh; 10 m)\left(4{,}5\,\text{kg}\cdot\text{m/s};\ 13{,}5\,\text{Dzh};\ 10\,\text{m}\right)
  4. (18 kg⋅m/s; 54 Dzh; 40 m)\left(18\,\text{kg}\cdot\text{m/s};\ 54\,\text{Dzh};\ 40\,\text{m}\right)
№ 56

Problem 56

Conservation laws: energy, work and power

A boy weighing 40 kg40\,\text{kg} climbs to the fifth floor in 2 min2\,\text{min}. Floor height 3 m3\,\text{m}. How much power does it develop?

  1. 80 Vt80\,\text{Vt}
  2. 400 Vt400\,\text{Vt}
  3. 40 Vt40\,\text{Vt}
  4. 20 Vt20\,\text{Vt}
№ 57

Problem 57

Conservation Laws: Momentum

A material point with a mass of 800 g800\,\text{g} moves in a circle of radius 40 cm40\,\text{cm} with a frequency of 5 rpm5\,\text{rpm}. Define impulse. What is the change in momentum over a period, half and quarter period?

  1. (10 kg⋅m/s; 0 kg⋅m/s; 20 kg⋅m/s; 14,15 kg⋅m/s)\left(10\,\text{kg}\cdot\text{m/s};\ 0\,\text{kg}\cdot\text{m/s};\ 20\,\text{kg}\cdot\text{m/s};\ 14{,}15\,\text{kg}\cdot\text{m/s}\right)
  2. (40 kg⋅m/s; 0 kg⋅m/s; 80 kg⋅m/s; 56,6 kg⋅m/s)\left(40\,\text{kg}\cdot\text{m/s};\ 0\,\text{kg}\cdot\text{m/s};\ 80\,\text{kg}\cdot\text{m/s};\ 56{,}6\,\text{kg}\cdot\text{m/s}\right)
  3. (200 kg⋅m/s; 0 kg⋅m/s; 400 kg⋅m/s; 283 kg⋅m/s)\left(200\,\text{kg}\cdot\text{m/s};\ 0\,\text{kg}\cdot\text{m/s};\ 400\,\text{kg}\cdot\text{m/s};\ 283\,\text{kg}\cdot\text{m/s}\right)
  4. (20 kg⋅m/s; 0 kg⋅m/s; 40 kg⋅m/s; 28,3 kg⋅m/s)\left(20\,\text{kg}\cdot\text{m/s};\ 0\,\text{kg}\cdot\text{m/s};\ 40\,\text{kg}\cdot\text{m/s};\ 28{,}3\,\text{kg}\cdot\text{m/s}\right)
№ 58

Problem 58

Conservation Laws: Momentum

A bullet of mass 10 g10\,\text{g} with a speed of 800 m/s800\,\text{m/s} pierces a ball of mass 2 kg2\,\text{kg} and leaves with a speed of 300 m/s300\,\text{m/s}. How high will the ball rise?

  1. 0,31 m0{,}31\,\text{m}
  2. 0,155 m0{,}155\,\text{m}
  3. 0,62 m0{,}62\,\text{m}
  4. 3,1 m3{,}1\,\text{m}
№ 59

Problem 59

Conservation laws: energy, work and power

A boy pulls a sled, applying a force of 8 N8\,\text{N} to the rope at an angle of 30∘30^{\circ}. For 15 s15\,\text{s} the sled traveled 30 m30\,\text{m}. Define work and power.

  1. (2080 Dzh; 139 Vt)\left(2080\,\text{Dzh};\ 139\,\text{Vt}\right)
  2. (208 Dzh; 13,9 Vt)\left(208\,\text{Dzh};\ 13{,}9\,\text{Vt}\right)
  3. (104 Dzh; 6,95 Vt)\left(104\,\text{Dzh};\ 6{,}95\,\text{Vt}\right)
  4. (416 Dzh; 27,8 Vt)\left(416\,\text{Dzh};\ 27{,}8\,\text{Vt}\right)
№ 60

Problem 60

Conservation laws: energy, work and power

Under the influence of a force of 34 N34\,\text{N}, a body with a mass of 2 kg2\,\text{kg} rose to a height of 15 m15\,\text{m} from a state of rest. Determine the kinetic energy at this height.

  1. 420 Dzh420\,\text{Dzh}
  2. 2100 Dzh2100\,\text{Dzh}
  3. 210 Dzh210\,\text{Dzh}
  4. 105 Dzh105\,\text{Dzh}
№ 61

Problem 61

Conservation laws: energy, work and power

A body of mass 2 kg2\,\text{kg} falls from a height of 8 m8\,\text{m}. Determine the kinetic energy at a height of 3 m3\,\text{m} above the Earth.

  1. 50 Dzh50\,\text{Dzh}
  2. 200 Dzh200\,\text{Dzh}
  3. 1000 Dzh1000\,\text{Dzh}
  4. 100 Dzh100\,\text{Dzh}
№ 63

Problem 63

Conservation Laws: Momentum

An icebreaker weighing 1000 t1000\,\text{t} collided with a stationary iceberg at a speed of 0,5 m/s0{,}5\,\text{m/s}. After the collision, the speed of the icebreaker became 0,2 m/s0{,}2\,\text{m/s}. Determine the mass of the iceberg, assuming joint motion.

  1. 25000 t25000\,\text{t}
  2. 2500 t2500\,\text{t}
  3. 1250 t1250\,\text{t}
  4. 5000 t5000\,\text{t}
№ 64

Problem 64

Conservation laws: energy, work and power

A bullet with a mass of 10 g10\,\text{g} has a kinetic energy of 3200 J3200\,\text{J}. Determine the recoil velocity of a rifle weighing 4 kg4\,\text{kg} and the work of the powder gases.

  1. (4 m/s; 6416 Dzh)\left(4\,\text{m/s};\ 6416\,\text{Dzh}\right)
  2. (20 m/s; 32080 Dzh)\left(20\,\text{m/s};\ 32080\,\text{Dzh}\right)
  3. (2 m/s; 3208 Dzh)\left(2\,\text{m/s};\ 3208\,\text{Dzh}\right)
  4. (1 m/s; 1604 Dzh)\left(1\,\text{m/s};\ 1604\,\text{Dzh}\right)
№ 65

Problem 65

Conservation laws: energy, work and power

A car weighing 20 t20\,\text{t} moves at a speed of 0,5 m/s0{,}5\,\text{m/s} towards a car weighing 30 t30\,\text{t} at a speed of 0,4 m/s0{,}4\,\text{m/s}. Determine the total velocity after the inelastic collision and the amount of heat generated by the collision.

  1. (−0,02 m/s; 2430 Dzh)\left(-0{,}02\,\text{m/s};\ 2430\,\text{Dzh}\right)
  2. (−0,08 m/s; 9720 Dzh)\left(-0{,}08\,\text{m/s};\ 9720\,\text{Dzh}\right)
  3. (−0,4 m/s; 48600 Dzh)\left(-0{,}4\,\text{m/s};\ 48600\,\text{Dzh}\right)
  4. (−0,04 m/s; 4860 Dzh)\left(-0{,}04\,\text{m/s};\ 4860\,\text{Dzh}\right)
№ 66

Problem 66

Conservation laws: energy, work and power

A car weighing 800 kg800\,\text{kg} moves at a speed of 54 km/h54\,\text{km/h}. The friction coefficient is 0,080{,}08. How much power does the engine develop and how much work does it do per minute with uniform motion?

  1. (9600 Vt; 5,76⋅105 Dzh)\left(9600\,\text{Vt};\ 5{,}76 \cdot 10^{5}\,\text{Dzh}\right)
  2. (4800 Vt; 2,88⋅105 Dzh)\left(4800\,\text{Vt};\ 2{,}88 \cdot 10^{5}\,\text{Dzh}\right)
  3. (19200 Vt; 1,152⋅106 Dzh)\left(19200\,\text{Vt};\ 1{,}152 \cdot 10^{6}\,\text{Dzh}\right)
  4. (96000 Vt; 5,76⋅106 Dzh)\left(96000\,\text{Vt};\ 5{,}76 \cdot 10^{6}\,\text{Dzh}\right)
№ 67

Problem 67

Conservation laws: energy, work and power

In a spring gun, the spring is compressed by 5 cm5\,\text{cm}. Determine the spring stiffness if a bullet of mass 8 g8\,\text{g} is fired at a speed of 5 m/s5\,\text{m/s}.

  1. 800 N/m800\,\text{N/m}
  2. 80 N/m80\,\text{N/m}
  3. 40 N/m40\,\text{N/m}
  4. 160 N/m160\,\text{N/m}
№ 68

Problem 68

Conservation laws: energy, work and power

An arrow of mass 40 g40\,\text{g} is shot vertically upward at a speed of 50 m/s50\,\text{m/s}. Determine its kinetic energy at an altitude of 100 m100\,\text{m}.

  1. 20 Dzh20\,\text{Dzh}
  2. 100 Dzh100\,\text{Dzh}
  3. 10 Dzh10\,\text{Dzh}
  4. 5 Dzh5\,\text{Dzh}
№ 69

Problem 69

Conservation laws: energy, work and power

The recoil speed of the gun barrel when fired is 20 m/s20\,\text{m/s}. Barrel mass 800 kg800\,\text{kg}, projectile mass 16 kg16\,\text{kg}. Determine the speed of the projectile.

  1. 500 m/s500\,\text{m/s}
  2. 2000 m/s2000\,\text{m/s}
  3. 10000 m/s10000\,\text{m/s}
  4. 1000 m/s1000\,\text{m/s}
№ 70

Problem 70

Conservation laws: energy, work and power

A body weighing 5 kg5\,\text{kg} when falling to Earth has a kinetic energy of 160 J160\,\text{J}. From what height did it fall?

  1. 3,2 m3{,}2\,\text{m}
  2. 1,6 m1{,}6\,\text{m}
  3. 6,4 m6{,}4\,\text{m}
  4. 32 m32\,\text{m}

THEORY

Lessons on the topic

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.

DIRECTORY

Formulas by topic

Body impulsep · kg m/sPowerP, N · WPeriodT · withWorkA · JAngular velocityω · rad/sFrequencyν · HzEnergyE, W · J