1. Magnetic noticeboard Forces Questions Medium Demand Miya uses a magnet to hold a notice on the noticeboard in her classroom. The board is coated in white plastic. Tick ONE box to show which material may be under the plastic coating for the magnet to stick to the board. steel paper wood cork Miya has four magnets. She wants to measure how much force is needed to pull each magnet away from the board. The picture below shows how she carries out her test. Write the label on the picture to name the equipment she uses to measure the force. (c) Miya measured the force for each magnet three times to calculate the average force. The table below shows her results. Magnet Average force needed to pull the magnet away (N) A 2 B 10 C 5 D 6 Which magnet is the strongest?
... (d) Miya observes that as she pulls on the magnet the force reading increases until the magnet comes away from the board. Tick ONE box to show when Miya should take the force reading. before she starts pulling on the magnet just before the magnet pulls away from the board just after she starts pulling on the magnet after the magnet is pulled away from the board (e) Give ONE reason why it is better to measure the force for each magnet three times instead of just once. 2. Tractor Rachel has a toy tractor and trailer. Both have magnets at each end. tractor magnet tractor magnet trailer magnet Rachel s pull trailer magnet When Rachel pulls the tractor, the trailer comes with it. Explain why the magnets cause the trailer to move forward when Rachel pulls on the tractor.... Rachel turns her trailer around. She pushes the trailer towards the tractor. The tractor moves away without touching the trailer. direction of Rachel s push tractor moves away Explain why the magnets cause the tractor to move away when Rachel pushes the trailer towards it.......
(c) Rachel puts some 20g masses in the trailer. She turns the trailer back around, so the tractor pulls the trailer again. Label the arrows on the picture below to say what forces they show. One force has been labelled for you. 20g masses (i)... (iii)... Rachel s pull (ii)... 2 marks (d) Rachel can put masses weighing 160g in the trailer before it separates from the tractor. She does this experiment on thick carpet. Rachel repeats her experiment on a new surface. This time, the trailer holds 240g before it separates from the tractor. Tick ONE box to predict the new surface Rachel tested. grass floorboards gravel path 3. Opposing Forces fluffy rug Some children are riding skateboards. It is easy to get hurt riding a skateboard. Look at the picture below. List TWO pieces of safety equipment that the children have used. (1)... (2)... Jane and Louis are facing in the same direction. They are on level ground and they are not moving. Jane gently pushes Louis on his skateboard. He moves forwards. As Louis moves, Jane also moves.
In which direction do Jane and her skateboard move when she pushes Louis? Tick ONE box. to her left backwards forwards to her right
(c) Jane and Louis go back to the same starting places. Jane gives Louis a bigger push on his skateboard. They both move faster this time. (i) What happens to the distance that Louis travels on this second push compared to the first push?... (ii) What happens to the distance that Jane travels on the second push compared to the first push?... (d) Dave goes over a jump on his skateboard. When he jumps he stays in the air for a short time. What force makes him return to the ground? 4. Measuring forces Lizzie uses a forcemeter. She measures the force needed to start a brick moving on different surfaces. Here are her results. Surface Pulling force (Newtons) A 19 B 30 C 16 D 6 Write A, B, C or D in each box below to put the surfaces in order of force needed to start the brick moving.
easiest surface to pull the brick on hardest surface to pull the brick on Lizzie uses the forcemeter to pull the brick on a table top. She spreads a spoonful of oil on the table top. She puts the brick on the oil. What happens when she tries pulling the brick on the oil? Tick ONE box. The brick moves more easily. The brick is harder to move. The brick will not move. (c) The brick floats. The diagram below shows three forces acting on the brick as it is pulled on each surface. A gravity B C force from the hand Force B makes it hard to start the brick moving. Write the name of Force B below. 5. Parachutes... Some children make four paper parachutes. Each parachute has a different sized canopy. They drop each parachute from the same height. They measure how long it takes each parachute to reach the ground. Here is a table of their results. Parachute Size (area) of Time to reach ground
canopy (cm 2 ) (seconds) A 100 1.0 B 400 2.0 C 625 2.5 D 900 3.0 Which parachute took the longest time to reach the ground?... The picture below shows two forces acting on a parachute as it falls. Write the name of the force up, on the line below. force up force down force up... (c) Look at the table of results. Describe how the time taken to reach the ground depends on the area of the canopy. 2 marks 6. Magnets Which TWO of these metals will attract the magnet? Tick TWO boxes. iron aluminium brass steel copper lead 2 marks
Complete the following sentences using either repel or attract. (i) (ii) The North pole of a magnet is held near the North pole of another magnet. The magnets... each other. The South pole of one magnet is held near the North pole of another magnet. The magnets... each other. 7. Helium Balloon The children have some balloons in the classroom. They have been filled with helium. When Robert lets his balloon go, it rises to the ceiling. Why does the balloon go up to the ceiling? Tick ONE box. The air is not pushing down on the balloon. There is less gravity pulling down on the balloon at the ceiling. The pull down on the balloon is less than the push up. The push up on the balloon is less than the pull down. Hilary puts twelve paperclips on the string of her balloon. The balloon stays at the same height above the floor of the classroom when she lets go. Explain why the forces acting on Hilary s balloon, with twelve paper clips on the string, make it stay at the same height. (c) What will happen to the movement of the balloon when she has thirteen paperclips on
the string? (d) Explain your answer to part (c) by describing the forces on the balloon.