2010 - JAMB Physics Past Questions and Answers - page 1

Since the cars are moving in the same direction, the velocity of a body A, V_a,relative to another body B, V_b is given by V = V_a - V_b

∴ the velocity of faster car is measured by the observer in the slower car is V = 130kmh^-1 - 100 kmh^-1 = 30 kmh^-1

The acceleration of free fall due to gravity is independent of mass of the body. Therefore, ignoring air resistance, which affects feather more than the stone, the stone and the feather will both reach the ground at the same time

Acceleration = (increase in velocity)/time taken

= (45 - 25)/10 = (20)/10 = 2ms^-2

Rough surface promotes friction. Therefore, roughness of conveyor belt prevents the load from slipping

Efficiency = (MA)/V.R x 100% = (load)/Effort x (1)/V.R

= (800)/400 x (1)/6 x 100% = 33.3%

Energy stored in a stretched wire (strain energy)

= average force x extension

= (1)/2 Fe

= (1)/2 x 300 N (30.5 - 30.0) x 10^-2 m

= (300)/2 x 0.5 x 10^-2 = 0.75J

Thrust = pressure x area = 100 pa x 3 m² = 300 N

Since relative density = mass of substance

mass of equal volume of water relative density bottle should be used to determine the mass of the substance, and mass of an equal volume of water by filling the bottle with the powder and water respectively and weighed with the beam balance.

The instrument used in measuring relative density is hydrometer

The low freezing point of alcohol, -115°c enable low temperatures to be measured. mercury freezes at 39°c, and cannot be used in countries like Russia where winter temperatures of -40°c are common