Physics Questions And Answers - Form 1 Term 2 Opener 2021

QUESTIONS

1.  
   1. Define masses and state its SI units. (2mks)
   2. Name the instruments used to measure mass. (4mks?)
2. Distinguish between a basic physical quantity and a derived physical quantity giving an example of each case. (3mks)
3.  
   1. Define force and state its SI unit. (2mks)
   2. State three effects of force when subject to an objects. (3mks)
   3. List any three types of forces. (3mks)
   4. State three properties of a good thermometric liquid (3mks)
4.  
   1. Differentiate between scalar and vector quantity. (2mks)
   2. The figure below shows a flask filled with coloured water. The rubber cork is pushed until the water rises a short distance in the glass tube
      
      When the flask is heated it is noted that the level of water first drops before it starts to rise. Explain this observation
5.  
   1. Define pressure and state its SI unit. (2mks)
   2. A brick 210cm long, 10cm wide and 5cm thick has a mass of 500g. Determine the
      1. Greatest pressure that can be exerted by the brick on a flat surface. (2mks)
      2. Least pressure that can be exerted by the brick on a flat surface.(3mks)
         (Take g=10N/KG)
6.  
   1. State any four differences between mass and weight.(4mks)
   2. A man has a mass of 70kg. Calculate:
      1. His weight on earth, where the gravitational field strength is 10N/KG. (2mks)
      2. His weight on the moon, where the gravitational field strength is 1.7N/kg.(2mks)
7. A block of wood of dimensions 25cm by 15cm by 5cm rests on a flat surface as shown
   Given that the weight of the block is 25N.Determine:
            
   
   1. The maximum pressure it exerts on the surface (3mks)
   2. The minimum pressure it exerts on the surface (3mks)
8. A text book has 1000 sheets bound between two covers each of thickness 0.10mm. Each sheet of paper is 0.05mm thick. Determine the thickness of the book.    (5mks)
9. Laboratory is a special room where the practical is done and where they store apparatus. State 6 safety rules that one must observe. (6mks)
10. Convert each of the following in as indicated.
    1. 10 tones into kg
    2. 256g into kg
    3. 1.25g into mg
11.  
    1. Define time and state its SI units. ( 2mks)
    2. Convert the following
       1. 24hrs into minutes
       2. 360 seconds into hours
12.  
    1. Define physics. (2mks)
    2. State and explain any two branches of physics.

MARKING SCHEME

1.  
   1. Define masses and state its SI units. (2mks)
      • mass of an object is the quantity of matter in it.
      • SI unit is kilogram(kg)
   2. Name the instruments used to measure mass. (4mks?)
      • Top pan balance
      • Beam balance
      • Lever balance
2. Distinguish between a basic physical quantity and a derived physical quantity giving an example of each case. (3mks)
   
   • Basic quantities are quantities that cannot be obtained from any other physical quantities e.g length, mass while derived quantities are quantities obtained by multiplication or division of basic quantities e.g volume, density.
3.  
   1. Define force and state its SI unit. (2mks)
      • force is push or a pull
      • SI unit of force is newton.
   2. State three effects of force when subject to an objects. (3mks)
      • Slow down or stop a moving object.
      • Change the direction of a moving object.
      • Distort/change the shape of an object.
      • Making stationary object start moving/increase the speed of a moving object.
   3. List any three types of forces. (3mks)
      • Gravitational
      • Tension
      • Up/thrust force
      • Magnetic force
      • Electrostatic force.
      • Conceptual force
      • Cohesive force
      • Molecular force
      • Nuclear force.
   4. State three properties of a good thermometric liquid (3mks)
      • be seen easily (visible)/opaque)
      • expand or contract uniformly
      • not stick to the inside of the tube (should not we the inside of the tube)
      • have a wide range of temperature (high boiling point and low freezing point)
4.  
   1. Differentiate between scalar and vector quantity. (2mks)
      • A quantity that has magnitude but no particular direction is described as scalar. A quantity that has magnitude and acts in a particular direction is described as vector.
   2. The figure below shows a flask filled with coloured water. The rubber cork is pushed until the water rises a short distance in the glass tube
      When the flask is heated it is noted that the level of water first drops before it starts to rise. Explain this observation
      • The initial fall of the level of the water is due to the expansion of the glass flask, which gets heated first. The water starts expanding when heat finally reaches it, and it rises up the tube.
5.  
   1. Define pressure and state its SI unit. (2mks)
      • pressure is the force acting normally(perpendicularly) per unit area.
      • SI unit pascal/newton per square meter(N/M²)
   2. A brick 210cm long, 10cm wide and 5cm thick has a mass of 500g. Determine the
      1. Greatest pressure that can be exerted by the brick on a flat surface. (2mks)
         Pmax=       f
                     asmallest
         Force= 500  x 10=5n
                     1000
         Area=0.10x0.05=0.005m²
              5n       = 1000NM²
         0.005m²
      2. Least pressure that can be exerted by the brick on a flat surface.(3mks
         (Take g=10N/KG)
         Pleast =       f         =       5          =250n/m
                     area(large)    0.20x0.10
6.  
   1. State any four differences between mass and weight.(4mks)
      

      Mass	Weight
      It is quality of matter in a body.	Is the pull of gravity on a body
      It is measured in kilogrammes	It is measured in newtons
      It is measured in newtons	Changes from places to places
      Measured using beam balance	Measured using spring balance
      Has magnitude only	Has magnitude and direction

   2. A man has a mass of 70kg. Calculate:
      1. His weight on earth, where the gravitational field strength is 10N/KG. (2mks)
         W=mg
         70x10=700n
      2. His weight on the moon, where the gravitational field strength is 1.7N/kg.(2mks)
         W=mg
         70x1.7=119n
7.  A block of wood of dimensions 25cm by 15cm by 5cm rests on a flat surface as shown
   Given that the weight of the block is 25N.Determine:
   1. The maximum pressure it exerts on the surface (3mks)
      Pmax =   F   
                 Amin
      Amin = 0.15 x 0.05
              = 0.0075m²
      Pmax =   25   
                  0.0075
              = 3333.3N/m²
   2. The minimum pressure it exerts on the surface (3mks)
      Pmin =    F   
                  Amax
      Amax = 0.25 x 0.15
      = 0.0375m²
      Pmin =    25    
                   0.0375
      = 666.67N/m²
8. A text book has 1000 sheets bound between two covers each of thickness 0.10mm. Each sheet of paper is 0.05mm thick. Determine the thickness of the book.   (5mks)
   Thickness of sheets = 1000 x 0.05
                                = 50mm
   Thickness of covers = 0.10 x 2
                                = 0.2mm
   Thickness of book = 50 x 0.2
                             = 50.2mm
9. Laboratory is a special room where the practical is done and where they store apparatus. State 6 safety rules that one must observe. (6mks)
   • Know emergency exit routes.
   • Avoid skin and eye contact with all chemicals.
   • Never leave containersof chemicals open
   • Minimize all chemical exposures.
   • Designated and well-marked waste storage locations are necessary.
   • Equipment should be maintained according to the manufacturer’s requirements and records of certification, maintenance, or repairs should be maintained for the life of the equipment.
     Any correct, rule award 1mk each
10. Convert each of the following in as indicated.
    1. 10 tones into kg
       10x1000=10000kg
    2. 256g into kg
        256  x 0.256kg=0.256kg
       1000
    3. 1.25g into mg
       1.25gx1000=1250 mg
11.  
    1. Define time and state its SI units. ( 2mks)
       • Time is a measure of duration of an event.
       • SI unit-second
    2. Convert the following
       1. 24hrs into minutes
          24x60=1440 munites
       2. 360 seconds into hours
           3600  = 1hr
          60x60
12.  
    1. Define physics. (2mks)
       • Physics is a natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force.
    2. State and explain any two branches of physics.
       • Mechanics,electrically and magnetism, thermodynamics geometrical optic wave, atomic
         Award 1mark for stating and 1 mark for explaining