D) steel wheels reduce friction, thus requiring less force to move the load. Friction between rubber and steel would be greater than steel and steel. Friction creates heat, which represents a loss of energy (which has to come from somewhere else - likely from the kinetic energy of the train)
The acceleration of the rock is the gravitational acceleration due to earth which is around 9.8 m/s^2. As the rock travels upwards it is working against the constant force of gravity and when it reaches the top it is the force of gravity that will cause a cause in the direction of the rocks velocity and cause it to accelerate towards earth. Using the equation a = F/m, the acceleration due to gravity exerts a force per unit mass on an object causing the object to accelerate, anything above earth surface will therefore have an external gravitational force action on it (in terms of projectile motion). So at the top of the rocks trajectory, the acceleration of the rock will be g (9.8) as a constant force is gravity is exerted on the rock throughout its path.
The object becomes neutralized in charge. The positive charge in the field neutralizes the negative charge in the object.
Answer:
The dose is 6 mSV
Explanation:
The absorbed dose (in gray - Gy) is the amount of energy that ionizing radiation deposits per unit mass of tissue. That is,
Absorbed dose = Energy deposited / Mass
while Dose equivalent (DE) (in Seivert -Sv) is given by
DE = Absorbed dose × RBE (Relative biological effectiveness)
First, we will determine the Absorbed dose
From the question, Energy deposited = 30mJ and Mass = 50kg
From,
Absorbed dose = Energy deposited / Mass
Absorbed dose = 30mJ/50kg
Absorbed dose = 0.6 mGy
Now, for the Dose equivalent (DE)
DE = Absorbed dose × RBE
From the question, RBE = 10
Hence,
DE = 0.6mGy × 10
DE = 6 mSv