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The body temperature of mammals (humans, furry animals & marine animals) ranges from 35°C – 38°C whereas birds have body temperature ranging from 40°C – 43°C. Exemplify how the body temperature of these vertebrates are maintained during a cold weather.
A coin is placed at the top of a two-story building, having a potential energy of 20 J. If it has a mass of 2.50 grams, what would be its velocity upon hitting the ground?
A 20 kg block (m1) and a bucket with mass m2 are connected by a light string that passes over a frictionless pulley as shown in Figure 2. The block lies on an incline plane of angle, α = 53.1° and the coefficient of kinetic friction between the block and the plane is 0.40. Calculate the mass of the hanging bucket, m2 if it is moving downward with the acceleration of 2.67 m/s 2
- The baton of a majorette is a uniform rod mass of 250g and length of 64cm. What is the moment of inertia of the baton about an axis passing through (a) its center? (b) at a point 20 cm from one end.
- What is the angular momentum of each hand of a clock? Treat the hands like a thin rod with an axis of rotation about one end. The minute hand is 25 cm long and has a mass of 46g. The hour hand is 15 cm long and has a mass of 32g.
A steel ball of mass 0.50 kg, moving with a velocity 2.0 m/s, strikes a second ball of mass 0.30 kg, initially at rest. The collision is a glancing one, causing the first ball to be deflected by an angle of 30°, with a speed of 1.50 m/s. Determine the velocity of the second ball after the collision, giving both its speed and direction. (6 marks)
A 34-g bullet travelling at 120 m/s embeds itself in a wooden block on a smooth surface. The block then slides toward a spring and collides with it. The block compresses the spring (k = 99 N/m) a maximum of 1.2 cm. Calculate the mass of the block of wood. (6 marks)
An 80 kg man standing at rest on a smooth, level ice surface throws a 200 g ball horizontally with a speed of 25 m/s, relative to Earth.
(a) With what speed and in what direction does the man move? (3 marks)
(b) If the man throws six such balls every 5.0 s, what is the average force acting on him? (3 marks)
Two men, of mass 100 kg each, stand on a cart of mass 300 kg. The cart can roll with negligible friction along a north-south track, and everything is initially at rest. One man runs towards the north and jumps off the cart at a speed of 5.0 m/s, relative to the cart. After he has jumped, the second man runs towards the south and jumps off the cart, again with a speed of 5.0 m/s relative to the cart. Calculate the speed and direction of the cart after both men have jumped off. (6 marks)
A nucleus, initially at rest, decays radioactively. In the process, it emits an electron horizontally to the east, with momentum 9.0 X 10–21 kg·m/s and a neutrino horizontally to the south, with momentum 4.8 X 10–21 kg·m/s.
(a) In what direction does the residual nucleus move? (3 marks)
(b) What is the magnitude of its momentum? (3 marks)
(c) If the mass of the residual nucleus is 3.6 X 10–25 kg, what is its recoil velocity? (3 marks)
A frictionless disc of mass 0.50 kg is moving in a straight line across an air table at a speed of 2.4 m/s when it bumps into an elastic band stretched between two fixed posts. If the elastic band exerts an average opposing force of 1.4 N on the disc for 1.5 s, what will be the final velocity of the disc?
