**1. Which of the following will reduce random errors in an experiment?**

**2. The best estimate for the time it takes light to cross the nucleus of the hydrogen atom is**

**3. Which is a unit of force?**

**4. Which of the following is a derived unit?**

**5. Which of the following is equivalent to the joule?**

**6. A boy jumps from a wall 3m high. What is an estimate of the change in momentum of the boy when he lands without rebounding?**

**7. The acceleration of free fall g is determined by the relationship**

`g=(4pi^2l)/t^2`. The uncertainty in the value of *l* is 2% and the uncertainty in the value of *t* is 5%. What is the uncertainty in *g*?

**8. The resistive force F acting on a sphere of radius r travelling with speed v through a liquid is given by the equation**

F = `6pietarv`

where η is a constant. What are the SI units of η?

**9. The sides of a square are measured to be 5.0 ± 0.2 cm. Which of the following gives the area of the square and its uncertainty?**

**10. A small object is attached to a string and rotated in a circle of constant radius in a horizontal plane. The tension T in the string is measured for different speeds v. Which of the following plots should give a straight-line graph?**

**11. A stone falls from rest to the bottom of a water well of depth d. The time t taken to fall is 2.0 ±0.2 s. The depth of the well is calculated to be 20 m using**

`d=1/2at^2.` The uncertainty in a is negligible.

What is the absolute uncertainty in *d*?

**12. The length of each side of a sugar cube is measured as 10 mm with an uncertainty of ± 2 mm . Which of the following is the absolute uncertainty in the volume of the sugar cube?**

**13. Which of the following lists three vector quantities?**

**14. Which of the following expresses the watt in terms of fundamental units?**

**15. Which of the following is a fundamental unit?**

**16. The maximum acceleration**

*a*_{max} of an oscillator undergoing simple harmonic motion (SHM) has a percentage uncertainty of 12%. The amplitude *x*_{0} of the oscillation has a percentage uncertainty of 20%. `ifk=sqrt(a_(max)/(x0)` what is the percentage uncertainty in the constant *k*?

**17. How many significant figures are there in the number 0.0450?**

**18. The radius of a sphere is measured with an uncertainty of 2%. What is the uncertainty in the volume of the sphere?**

**19. Which of the following is a scalar quantity?**

**20. A student measures the radius r of a sphere with an absolute uncertainty Δr. What is the fractional uncertainty in the volume of the sphere?**

**21. What is the unit of energy density?**

**22. A swimming pool contains**

18×10^{6} kg of pure water. The molar mass of water is 18gmol^{–1}. What is the correct estimate of the number of water molecules in the swimming pool?

**23. An object is positioned in a gravitational field. The measurement of gravitational force acting on the object has an uncertainty of 3 % and the uncertainty in the mass of the object is 9 %. What is the uncertainty in the gravitational field strength of the field?**

**24. A car moves north at a constant speed of 3m**

s^{–1} for 20s and then east at a constant speed of 4m s^{–1} for 20s. What is the average speed of the car during this motion?

**25. What is the correct SI unit for momentum?**

**26. The diagram below shows the forces acting on a block of weight W as it slides down a slope. The angle between the slope and the horizontal is θ, the normal reaction force on the block from the slope is N and friction is negligible.**

Which of the following gives the resultant force on the block?

**27. What is the best estimate for the diameter of a helium nucleus?**

**28. Which of the following lists two scalar quantities?**

**29. Which of the following is a unit of energy?**

**30. A body accelerates from rest with a uniform acceleration a for a time t. The uncertainty in a is 8% and the uncertainty in t is 4%. The uncertainty in the speed is**

**31. The force of air resistance F that acts on a car moving at speed v is given by**

*F*=*kv*^{2} where *k* is a constant. What is the unit of *k*?

**32. The masses and weights of different objects are independently measured. The graph is a plot of weight versus mass that includes error bars.**

These experimental results suggest that the

**33. An object slides down an inclined plane that makes an angle θ with the horizontal. The weight of the object is W.**

Which of the following is the magnitude of the component of the weight parallel to the plane?

**34. What is the order of magnitude of the mass, in kg, of an apple?**

**35. A volume is measured to be**

52 mm^{3}. This volume in m^{3} is

**36. Which of the following is a fundamental SI unit?**

**37. The length of the side of a cube is 10.0 ±0.3cm. What is the uncertainty in the volume of the cube?**

**38. Which is a vector quantity?**

**39. Two pulses are travelling towards each other.**

What is a possible pulse shape when the pulses overlap?

**40. Light of wavelength 400nm is incident on two slits separated by 1000µm. The interference pattern from the slits is observed from a satellite orbiting 0.4Mm above the Earth. The distance between interference maxima as detected at the satellite is**

**41. What is the unit of electrical energy in fundamental SI units?**

**42. An object falls for a time of 0.25 s. The acceleration of free fall is**

9 .81 ms^{−2}. The displacement is calculated. Which of the following gives the correct number of significant digits for the calculated value of the displacement of the object?

**43. A velocity of 5 m**

s^{−1} can be resolved along perpendicular directions XY and XZ.

The component of the velocity in the direction XY is of magnitude 4 m s^{−1}. What is the magnitude of the component in the direction XZ?

**44. The diagram shows an analogue meter with a mirror behind the pointer.**

What is the main purpose of the mirror?

**45. The graph shows the relationship between two quantities p and q. The gradient of the graph is r and the intercept on the p axis is s.**

Which of the following is the correct relationship between *p* and *q*?

**46. Which of the following contains one fundamental and one derived unit?**

**47. The current I through a resistor is measured with a digital ammeter to be 0.10 A. The uncertainty in the calculated value of**

*I*^{2} will be

**48. A stone attached to a string is moving in a horizontal circle. The constant speed of the stone is v. The diagram below shows the stone in two different positions, X and Y.**

**49. The vector diagram shows two forces acting on a point object O. The forces are in the plane of the page.**

Another 5 N force is applied to O in the plane of the page. Which of the following gives the direction of this force to ensure that O is in equilibrium?

**50. Aiming for the centre of a target, an archer fires arrows which produces a pattern of hits as shown below.**

The pattern suggests the presence of

**51. The graph shows a set of experimental results to determine the density of oil. The results have systematic errors and random errors.**

Using the information on the graph, what can be said about the measurements used to find the density of oil?

**52. A sphere fits inside a cube.**

The length of the cube and the diameter of the sphere are 10.0±0.2cm.

What is the ratio