posted by lawrence .
( 1.) A passenger in a moving car and a passerby standing at the road side see each other as moving in the opposite direction. Which of the following is not true?<
(A) The passenger is in motion relative to the passer-by
(B) The passer-by is stationery relative to the passenger
(C) Both observers are in motion relative to each other
(D) The passer-by is in motion relative to the passenger
( 2.) Which of the following statements is not correct about reference frames?
(A) Laws of physics are invariant in inertial reference frames
(B) In non-inertial reference frames the motion of objects depend only on the interactions of constituent particles among themselves
(C) Any reference frame moving at constant velocity with respect to an inerial refernce frame is also inertial
(D) If the coordinate axes of a reference frame attached to an object remain fixed in space then the object is at rest
( 3.) What are the dimensions of power (time rate of change of expending energy)
( 4.) Express the speed of a car traveling at 80km/hr in mm/s
( 5.) Two forces act on a point object as follows: 100N at 170derees and 100N at 50degrees. Find their resultant force
110N at 50degrees
100N at 110degrees
100N at 50degrees
( 6.) Given three vectors a = -i-4j+2k, b = 3i+2j-2k, c = 2i-3j+k, calculate a.(bxc)
( 7.) The resultant of vectors A and B has a magnitude of 20 units. A has a magnitude of 8 units, and the angle between A and B is 40degrees. Calculate the magnitude of B
( 8.) A man leaves the garrage in his house and drives to a neighbouring town which is twenty kilometres away from his house on sight-seeing. He returnes home to his garrage two hours after. What is his average velocity from home in Km/h?
( 9.) A monkey in a perch 20m high in a tree drops a coconut above the head of a zoo keeper as he runs with a speed 1.5m/s benaeth the tree. How far behind him in metres does the coconut hit the ground?
( 10.) A monkey in a perch 20m high in a tree drops a coconut above the head of a zoo keeper as he runs with a speed 1.5m/s benaeth the tree actually intending to hit the toes of the zoo keeper, how early in seconds should the coconut be dropped by the monkey to achieve his aim?
( 11.) Which of the follwing statements is correcct?
An object can have a constant velocity even though its speed is changing
An object can have a constant speed even though its velocty is changing
An object can have zero acceleration and eventually reverses its direction
An object can have constant velocity even though its acceleration is not zero
( 12.) A boat propelled so as to travel with a speed of 0.50m/s in still water, moves directly (in a straight line) across a river that is 60m wide. The river flows with a speed of 0.30m/s. How long in seconds does it take the boat to cross the river?
( 13.) A boy intends to move an m kg - crate across the floor by applying a constant force P newtons on it.The coeficient of friction between the floor and the crate is µ. Which of these is the best option for his task?
Pull the crate with P applied horizontally
Push the crate with P inclined at an angle above the horizontal
Pull the crate with P inclined at an angle above the horizontal
Pull the crate with P inclined an angle below the horizontal
( 14.) A 50kg boy suspends himself from a point on a rope tied horizontally between two vertical poles. The two segments of the rope are then inclined at angles 30 degrees and 60 degrees respectively to the horizontal.The tensions in the segments of the rope in newtons are
25.0 and 43.3
50.0 and 25.0
100.0 and 43.5
100.0 and 25.0
( 15.) Which of the following physical concepts best explains why passengers in fast moving cars should always fasten their seat-belts?
( 16.) Which of the following does not contribute to the determination of stability of on an object?
( 17.) A rope suspended from a ceiling supports an object of weight W at its opposite end. Another rope tied to the first at the middle is pulled horizontally with a force of 30N. The junction P of the ropes is in equilibrium. Calculate the weight W and the tension T in the upper part of the first rope
27.2N and 39.2N
40.5N and 62.5N
30.4N and 53.7N
16.6N and 27.3N
( 18.) A 150-kg ladder leans against a smooth wall, making an angle of 30 degrees with the floor. The centre of gravity of the ladder is one-third the way up from the bottom. How large a horizontal force must the floor provide if the ladder is not to slip?
( 19.) A body hangs from a spring balance supported from the roof of an elavator. If the elavator has an upward acceleration of 3m/s2 and the balance reads 50N, what is the true weight of the body?