## Potential difference equation

3 questions about Potential difference equation

1. An electric charge is moved in a homogeneous electric field with a force of 2√3 N a distance of 20 cm. If the direction of the force is at an angle of 30o to the displacement of the electric charge, what is the difference in the electric potential energy at the initial and final positions of the electric charge.

Known:

Force (F) = 2√3 N

Distance (s) = 20 cm = 0.2 m

Angle (θ) = 30o

Wanted: Electric potential difference

Solution:

## Angular velocity equation

3 questions about Angular velocity equation

1. An object moving in a circular path has a radius of 0.5 m. The particle is able to cover an angle of 60π rad in 15 seconds. Determine the angular speed of the object.

Known:

Time interval (t) = 15 seconds

Wanted: Angular velocity (ω)

Solution:

## The resultant force equation

3 questions about The resultant force equation

1. A car with a mass of 5 tonnes moves from rest in 50 seconds, reaching a speed of 72 km/hour. The force on the car is…

Known:

Mass (m) = 5 tons = 5000 kg

Initial speed (vo) = 0

Final speed (vt) = 72 km/h = 20 m/s

Time interval (t) = 50 seconds

Wanted: Force (F)

Solution:

## Impulse equation

1. A car with a mass of 250 kg is moving with a speed of 72 km/hour, then accelerated with a constant force so that in 5 seconds its speed becomes 80 km/hour. Determine the impulse for 5 seconds

Known:

The mass of the car (m) = 250 kg

Initial speed (vo) = 72 km/h = 20 m/s

Final speed (vt) = 80 km/h = 22 m/s

Time interval (t) = 5 seconds

Wanted: Determine impulse (I)

Solution:

## Friction force equation

3 questions about Friction force equation

1. Block A 3 kg is placed on the table and then tied to a rope that is connected to stone B = 2 kg through a pulley as shown. The mass and friction of the pulleys are neglected. Acceleration due to gravity g = 10 m/s2. Determine the acceleration of the system and the tension in the rope if:

a) smooth table b) rough table with a coefficient of kinetic friction of 0.4

Known:

The mass of block A (mA) = 3 kg

The mass of rock B (mB) = 2 kg

Acceleration due to gravity (g) = 10 m/s2

Weight of block A (wA) = m g = (3)(10) = 30 Newton

Weight of rock B (wB) = m g = (2)(10) = 20 Newton

Wanted: The acceleration of the system (a) and the tension in the rope (T)

Solution:

## Normal force equation

3 questions about Normal force equation

1. A block has a mass of 5 kg. If g = 10 m/s2, determine:

a) the weight of the block

b) the normal force if the block is placed on a flat plane

c) the normal force if the block rests on an inclined plane that forms an angle of 30o to the horizontal

Known:

The mass of the block (m) = 5 kg

Acceleration due to gravity (g) = 10 m/s2

Wanted: w, N on the plane and N on the incline

Solution:

## Rope tension equation

3 Questions about Rope tension equation

1. The picture below shows three blocks, namely A, B and C which are located on a smooth horizontal plane. If mass A = 1 kg, mass B = 2 kg and mass C = 2 kg and F = 10 N, then determine the ratio of the tension in the rope between A and B to the tension in the rope between B and C.

Known: The mass of A (mA) = 1 kg

Mass B (mB) = 2 kg

The mass of C (mC) = 2 kg

Tensile force (F) = 10 N

Wanted: TAB : TBC

Solution:

## Moment of inertia equation

3 Problems and solutions about Moment of inertia equation

1. A solid cylinder has a radius of 8 cm and a mass of 2 kg. Meanwhile, a solid ball has a radius of 5 cm and a mass of 4 kg. If the two objects rotate with an axis through their center, determine the ratio of the moment of inertia of the cylinder and the ball.

Known:

Solid cylinder radius (r) = 8 cm = 0.08 m

Solid cylinder mass (m) = 2 kg

Solid ball radius (r) = 5 cm = 0.05 m

The mass of the solid ball (m) = 4 kg

Wanted: Comparison of the moment of inertia of a cylinder and a ball

Solution:

## Momentum equation

3 problems and solutions about Momentum equation

1. If the object’s speed becomes 5 times its original speed, then the object’s momentum becomes ….. its original momentum.

Known:

Initial speed = v

Final speed = 5v

Mass = 1

Wanted: Momentum

Solution:

## Speed equation

3 problems and solutions about the Speed equation

1. A car travels to the south for 100 m in 1 minute then turns to the east 120 m in 0.5 minutes. Determine the average speed of the car.

Known:

Total distance = 100 meters + 120 meters = 220 meters

Total time = 1 minute + 0.5 minutes = 1.5 minutes = 90 seconds

Wanted: Average speed

Solution: