Tuesday, 23 September 2014

Newton's Laws of Motion

Question 1
During take-off, an aircraft accelerates at 3·4ms-2. The total mass of the aircraft is 103kg.
a)the net force acting on the aircraft during the acceleration
b)the speed of the aircraft after 5 seconds of acceleration.
Question 2
A person on a bicycle is moving at 15ms-1 on a horizontal road. The total mass of the person plus the bicycle is 90kg. The person stops pedalling and comes to rest in 12s. Calculate the average magnitude of the force causing the bicycle to slow down.
Question 3
A mass m = 2·5kg is being accelerated upwards by the tension in a string, as shown below.
The magnitude of the acceleration a = 4ms-2. If the acceleration due to gravity is g = 10ms-2, calculate the magnitude of the tension in the string.
Question 4
A person stands in an elevator. The person has a mass of 60kg. Calculate the apparent weight of the person when the elevator is accelerating downwards at 2·5ms-2.
Question 5
A block of wood of mass m = 250g is being pulled along a surface by a force F = 20N. The force of friction between the block and the surface has a magnitude of 15N, see diagram below.
a)the acceleration of the block
b)the distance moved, starting from rest, in 5s.
Question 6
The diagram below shows two masses hanging on a string passing over a light, frictionless pulley.
a)Calculate the acceleration of the masses, given that m1 = 3kg and m2 = 1.5kg.
b)Calculate the magnitude of the tension in the string when the masses are accelerating.
Question 7
In the diagram below, the object placed on the right hand scale pan has a mass M = 250g and it causes both scale pans to accelerate at 2.45ms-2. The scale pans themselves each have a mass m.
a)Draw a diagram showing the forces which are acting on the mass M.
b)Find the force which the mass M exerts on the scale pan.
c)Assuming that the pulley moves without friction and has negligible mass, calculate the total mass of the two scale pans.