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10TH GRADE PRACTICE

Physics Problems: Dynamics, Grade 10

Newton's laws and fundamental forces.

20 problems2 subtopics
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CONDITIONS

Problems

20
№ 35

Problem 35

Dynamics: Newton's laws

What force must be applied to a lead block with a volume of 40 cm340\,\text{cm}^{3} so that it moves with an acceleration of 5 m/s25\,\text{m/s}^{2}? How much will a dynamometer spring with a stiffness of 120 N/m120\,\text{N/m} stretch if this block is suspended from it?

  1. (22,6 N; 0,377 m)\left(22{,}6\,\text{N};\ 0{,}377\,\text{m}\right)
  2. (2,26 N; 0,0377 m)\left(2{,}26\,\text{N};\ 0{,}0377\,\text{m}\right)
  3. (1,13 N; 0,01885 m)\left(1{,}13\,\text{N};\ 0{,}01885\,\text{m}\right)
  4. (4,52 N; 0,0754 m)\left(4{,}52\,\text{N};\ 0{,}0754\,\text{m}\right)
№ 36

Problem 36

Dynamics: Newton's laws

A force imparts an acceleration of a1a_1 to a body of mass m1m_1, and an acceleration of a2a_2 to a body of mass m2m_2. What acceleration will this force impart to a body of mass m1+m2m_1+m_2?

  1. a=a1+a22, [a]=m/s2a=\dfrac{a_1+a_2}{2},\ [a]=\text{m/s}^{2}
  2. a=a1−a2a1+a2, [a]=m/s2a=\dfrac{a_1-a_2}{a_1+a_2},\ [a]=\text{m/s}^{2}
  3. a=a1a2a1+a2, [a]=m/s2a=\dfrac{a_1a_2}{a_1+a_2},\ [a]=\text{m/s}^{2}
  4. a=a1+a2, [a]=m/s2a=a_1+a_2,\ [a]=\text{m/s}^{2}
№ 37

Problem 37

Dynamics: forces and balance

A sled with a load of mass 50 kg50\,\text{kg} is subject to a horizontal force of 40 N40\,\text{N}. With what acceleration does the sled move if the coefficient of friction is 0,020{,}02?

  1. 0,3 m/s20{,}3\,\text{m/s}^{2}
  2. 1,2 m/s21{,}2\,\text{m/s}^{2}
  3. 6 m/s26\,\text{m/s}^{2}
  4. 0,6 m/s20{,}6\,\text{m/s}^{2}
№ 38

Problem 38

Dynamics: Newton's laws

The force 4 N4\,\text{N} gives the body an acceleration of 1,25 m/s21{,}25\,\text{m/s}^{2}. What force will impart an acceleration of 3 m/s23\,\text{m/s}^{2} to this body?

  1. 9,6 N9{,}6\,\text{N}
  2. 4,8 N4{,}8\,\text{N}
  3. 19,2 N19{,}2\,\text{N}
  4. 96 N96\,\text{N}
№ 39

Problem 39

Dynamics: Newton's laws

With what acceleration does a rocket with a mass of 200 kg200\,\text{kg} take off from the Earth if the thrust force of the engine is 3 kN3\,\text{kN}?

  1. 50 m/s250\,\text{m/s}^{2}
  2. 5 m/s25\,\text{m/s}^{2}
  3. 2,5 m/s22{,}5\,\text{m/s}^{2}
  4. 10 m/s210\,\text{m/s}^{2}
№ 40

Problem 40

Dynamics: forces and balance

With what force do the Earth and the Sun attract? Take MZ=6⋅1024 kgM_{\text{Z}}=6\cdot10^{24}\,\text{kg}, MS=2⋅1030 kgM_{\text{S}}=2\cdot10^{30}\,\text{kg}, r=1,5⋅1011 mr=1{,}5\cdot10^{11}\,\text{m}. What diameter would a steel cable hold the Earth with a tensile strength of 500⋅106 Pa500\cdot10^{6}\,\text{Pa}?

  1. (7,12⋅1022 N; 1,9⋅107 m)\left(7{,}12 \cdot 10^{22}\,\text{N};\ 1{,}9 \cdot 10^{7}\,\text{m}\right)
  2. (3,56⋅1023 N; 9,5⋅107 m)\left(3{,}56 \cdot 10^{23}\,\text{N};\ 9{,}5 \cdot 10^{7}\,\text{m}\right)
  3. (3,56⋅1022 N; 9,5⋅106 m)\left(3{,}56 \cdot 10^{22}\,\text{N};\ 9{,}5 \cdot 10^{6}\,\text{m}\right)
  4. (1,78⋅1022 N; 4,75⋅106 m)\left(1{,}78 \cdot 10^{22}\,\text{N};\ 4{,}75 \cdot 10^{6}\,\text{m}\right)
№ 41

Problem 41

Dynamics: forces and balance

A body of mass 6 kg6\,\text{kg} is moved along a table, the coefficient of friction is 0,20{,}2. What force must be applied for uniform motion and for motion with acceleration 1,5 m/s21{,}5\,\text{m/s}^{2}? What will happen at forces 5 N5\,\text{N} and 15 N15\,\text{N}?

  1. (6 N; 10,5 N; 0 m/s2; 0,25 m/s2)\left(6\,\text{N};\ 10{,}5\,\text{N};\ 0\,\text{m/s}^{2};\ 0{,}25\,\text{m/s}^{2}\right)
  2. (24 N; 42 N; 0 m/s2; 1 m/s2)\left(24\,\text{N};\ 42\,\text{N};\ 0\,\text{m/s}^{2};\ 1\,\text{m/s}^{2}\right)
  3. (120 N; 210 N; 0 m/s2; 5 m/s2)\left(120\,\text{N};\ 210\,\text{N};\ 0\,\text{m/s}^{2};\ 5\,\text{m/s}^{2}\right)
  4. (12 N; 21 N; 0 m/s2; 0,5 m/s2)\left(12\,\text{N};\ 21\,\text{N};\ 0\,\text{m/s}^{2};\ 0{,}5\,\text{m/s}^{2}\right)
№ 42

Problem 42

Dynamics: forces and balance

Masses of masses 4 kg4\,\text{kg} and 24 kg24\,\text{kg} are suspended from the ends of a weightless lever. The distance from the fulcrum to the smaller load is 60 cm60\,\text{cm}. Determine the length of the lever.

  1. 70 sm70\,\text{sm}
  2. 35 sm35\,\text{sm}
  3. 140 sm140\,\text{sm}
  4. 700 sm700\,\text{sm}
№ 43

Problem 43

Dynamics: forces and balance

A beam with a mass of 600 kg600\,\text{kg} rests on two supports. One support is located at the end of the beam, the other at a distance of a quarter of the length from the other end. With what force does the beam press on the supports?

  1. (20000 N; 40000 N)\left(20000\,\text{N};\ 40000\,\text{N}\right)
  2. (2000 N; 4000 N)\left(2000\,\text{N};\ 4000\,\text{N}\right)
  3. (1000 N; 2000 N)\left(1000\,\text{N};\ 2000\,\text{N}\right)
  4. (4000 N; 8000 N)\left(4000\,\text{N};\ 8000\,\text{N}\right)
№ 44

Problem 44

Dynamics: Newton's laws

A person weighing 80 kg80\,\text{kg} presses on the elevator floor with a force of 700 N700\,\text{N}. Determine the magnitude and direction of acceleration of the elevator.

  1. 0,8 m/s2 vniz0{,}8\,\text{m/s}^{2}\ \text{vniz}
  2. 0 m/s20\,\text{m/s}^{2}
  3. 1,25 m/s2 vniz1{,}25\,\text{m/s}^{2}\ \text{vniz}
  4. 1,25 m/s2 vverkh1{,}25\,\text{m/s}^{2}\ \text{vverkh}
№ 45

Problem 45

Dynamics: forces and balance

Under the action of a horizontal force 12 N12\,\text{N}, a block of mass 5 kg5\,\text{kg} moves with an acceleration of 2 m/s22\,\text{m/s}^{2}. Determine the coefficient of friction.

  1. 0,02 dimensionless0{,}02\,\text{dimensionless}
  2. 0,08 dimensionless0{,}08\,\text{dimensionless}
  3. 0,4 dimensionless0{,}4\,\text{dimensionless}
  4. 0,04 dimensionless0{,}04\,\text{dimensionless}
№ 46

Problem 46

Dynamics: forces and balance

A body of mass 5 kg5\,\text{kg} falls from a height of 20 m20\,\text{m} in 2,1 s2{,}1\,\text{s}. Determine the force of air resistance. Take g=9,81 m/s2g=9{,}81\,\text{m/s}^{2}.

  1. 3,7 N3{,}7\,\text{N}
  2. 1,85 N1{,}85\,\text{N}
  3. 7,4 N7{,}4\,\text{N}
  4. 37 N37\,\text{N}
№ 47

Problem 47

Dynamics: Newton's laws

The force 6 N6\,\text{N} gives the body an acceleration of 0,4 m/s20{,}4\,\text{m/s}^{2}. What force will give this body an acceleration of 5 m/s25\,\text{m/s}^{2}?

  1. 750 N750\,\text{N}
  2. 75 N75\,\text{N}
  3. 37,5 N37{,}5\,\text{N}
  4. 150 N150\,\text{N}
№ 48

Problem 48

Dynamics: forces and balance

A body of mass 2 kg2\,\text{kg} moves along a horizontal surface under the action of a force 5 N5\,\text{N}. The friction coefficient is 0,40{,}4. What is the formal result of calculating acceleration using a sliding model?

  1. −3 m/s2-3\,\text{m/s}^{2}
  2. −15 m/s2-15\,\text{m/s}^{2}
  3. −1,5 m/s2-1{,}5\,\text{m/s}^{2}
  4. −0,75 m/s2-0{,}75\,\text{m/s}^{2}
№ 49

Problem 49

Dynamics: forces and balance

What must be the coefficient of friction so that a motorcyclist can negotiate a turn with a radius of 50 m50\,\text{m} at a speed of 36 km/h36\,\text{km/h}?

  1. 0,1 dimensionless0{,}1\,\text{dimensionless}
  2. 0,4 dimensionless0{,}4\,\text{dimensionless}
  3. 2 dimensionless2\,\text{dimensionless}
  4. 0,2 dimensionless0{,}2\,\text{dimensionless}
№ 50

Problem 50

Dynamics: Newton's laws

A person weighing 50 kg50\,\text{kg} presses on the elevator floor with a force of 600 N600\,\text{N}. Determine the acceleration of the elevator.

  1. 2 m/s22\,\text{m/s}^{2}
  2. 1 m/s21\,\text{m/s}^{2}
  3. 4 m/s24\,\text{m/s}^{2}
  4. 20 m/s220\,\text{m/s}^{2}
№ 51

Problem 51

Dynamics: forces and balance

At what speed must a cyclist travel in order to exert pressure on the bridge at the top point of a bridge with a radius of curvature of 45 m45\,\text{m} with a force half that of gravity?

  1. 150 m/s150\,\text{m/s}
  2. 15 m/s15\,\text{m/s}
  3. 7,5 m/s7{,}5\,\text{m/s}
  4. 30 m/s30\,\text{m/s}
№ 52

Problem 52

Dynamics: forces and balance

What is the force holding a car of mass 1200 kg1200\,\text{kg} around a curve of radius 250 m250\,\text{m} at a speed of 90 km/h90\,\text{km/h}? What is the maximum speed with a coefficient of friction of 0,50{,}5?

  1. (6000 N; 70,72 m/s)\left(6000\,\text{N};\ 70{,}72\,\text{m/s}\right)
  2. (30000 N; 353,6 m/s)\left(30000\,\text{N};\ 353{,}6\,\text{m/s}\right)
  3. (3000 N; 35,36 m/s)\left(3000\,\text{N};\ 35{,}36\,\text{m/s}\right)
  4. (1500 N; 17,68 m/s)\left(1500\,\text{N};\ 17{,}68\,\text{m/s}\right)
№ 53

Problem 53

Dynamics: Newton's laws

The elevator moves with an acceleration of 2 m/s22\,\text{m/s}^{2}. The load presses on the floor with a force of 2880 N2880\,\text{N}. What two masses of a load are possible depending on the direction of acceleration?

  1. (120 kg; 180 kg)\left(120\,\text{kg};\ 180\,\text{kg}\right)
  2. (480 kg; 720 kg)\left(480\,\text{kg};\ 720\,\text{kg}\right)
  3. (2400 kg; 3600 kg)\left(2400\,\text{kg};\ 3600\,\text{kg}\right)
  4. (240 kg; 360 kg)\left(240\,\text{kg};\ 360\,\text{kg}\right)
№ 62

Problem 62

Dynamics: forces and balance

A ball of mass 500 g500\,\text{g} hangs on a thread of length 80 cm80\,\text{cm}. He is given 90∘90^{\circ} and released. Determine the thread tension at the lowest point.

  1. 15 N15\,\text{N}
  2. 7,5 N7{,}5\,\text{N}
  3. 30 N30\,\text{N}
  4. 150 N150\,\text{N}

THEORY

Lessons on the topic

Free fall and circular motionFall without resistance and kinematics of uniform rotation.Newton's lawsRelationship between forces and acceleration and interaction of bodies.Strength and BalanceGravity, elasticity, friction, inclined plane and moment of force.

DIRECTORY

Formulas by topic

Body weightP · NSpring stiffnessk · N/mFriction coefficientμ · dimensionlessmoment of forceM · NmPeriodT · withDistance and pathS, l · mStrengthF · NAngular velocityω · rad/sElongationΔl · mFrequencyν · Hz