Mechanics | Relativity Answers

A child throws a 0.50 kg snowball at his friend at 12.0 m/s but the snowball lands on the ground in front of his friend.

The snowball is 1.3 m above the ground when it leaves the child’s hand.

(a) What is the (i) kinetic energy & (ii) potential energy of the snowball at the time of release?

(b) What is the total energy of the snowball (i) at the time of release & (ii) just before it hits the ground?

(c) What is the snowball’s kinetic energy just before it hits the ground in front of his friend?

(d) How fast is the snowball moving just before it hits the ground in front of his friend?

A toboggan carrying two children (total mass = 85 kg) reaches its maximum speed at the bottom of a hill, and then glides to a stop in 21 m along a horizontal surface.The coefficient of kinetic friction between the toboggan and the snowy surface is 0.11.

(a) Draw a FBD of the toboggan as it slows down, and calculate the magnitude of ALL the forces in the diagram.

(b) Calculate the acceleration of the toboggan.

(c) Calculate the work done on the toboggan by the friction on the snowy surface.Should the work be positive or negative?Explain.

A 2 kg rectangular thin plate has a length of 0.5 m and a width of 0.20. the moment of inertia

of the plate is 0.29 kg-m2

. Where is the location of the axis of rotation?

The displacement of an object is given by x =sin2pi (t+0.01)m. Find amplitude of the oscillatory motion ,time period, maximum velocity , maximum acceleration and initial displacement

The specific weight of an unknown liquid is 12 400 N/me. What mass of the liquid is contained in a volume of 500 cm3? Use: the minimum value of gravity on the earth

Andrea has a particularly old bike, and she has not lubricated the chain or gears. This causes friction inside the gears as she rides. She begins coasting on flat ground at a speed of 10 m/s, and after a few seconds is only going 8 m/s. How much energy has been converted to heat?

A piano wire 0.5m longlong has a total mass of 0.01kg and is stretched with a tension ofof 800N. calculate the tension of the wire when it sounds it's fundamental note.

A hiker travels 4,5 km in a direction 12 degrees south of west and then 7,2 km in a direction 23 degrees west of south.

Determine the hiker’s overall displacement.

Draw each of the hiker’s individual displacement vectors on the same set of Cartesian axes, so that their initial points coincide at

the skin is the largest organ in the human body.For a human adult the average area of the skin surface is about 1.80m2 how much squared foot is this area

The viscosity of a fluid is to be measured by a viscometer constructed of two 3m long concentric cylinders.the inner diameter of the outer cylinder is 35cm, and the gap between the two cylinders is 0.14cm.the outer cylinder is rotated at 250rpm. and the torque is measured to be 1.8N determine the viscosity of the fluid