No, both the cars do not have the same velocity.
Velocity is a vector quantity and it is the rate of change of displacement with time or change in speed with direction.
Velocity has both magnitude and direction. So when you are in a car going 70 km/h and another car goes in the opposite direction at 70 km/h their velocities are different.
How?
Consider your car as moving in the positive direction, so its velocity will be 70 km/h and for the car moving in the opposite direction, since the direction is opposite, the velocity of that car will be -70 km/h. This is because, the velocity is a vector quantity that has both magnitude and direction. For one car, the direction is positive and for the other one the direction is negative.
Answer: heat flows from the hot water to cold water
Explanation:
Heat transfer is taken place from higher temperature to lower temperature then hot water gives heat to the cold water. There are three methods of conduction , Those are Conduction , Convection and Radiation here the heat transfer is taken place from convection.
Answer:
convection currents is the answer
Answer: the pair of sunglasses
Explanation:
A good pair of sunglasses are composed of abosorbent lenses that filter the sunlight that affects the eyes retina, especially ultraviolet (UV). So, these sunglasses are used to reduce the amount of light or radiant energy transmitted.
On the other hand, normal reading glasses (in which the lens glass has not been treated to filter ultraviolet sunlight) will let UV rays pass through.
Therefore, if both glasses are exposed to sunlight, the sunglasses are expected to be warmer by absorbing that radiant energy and preventing it from reaching the eyes.
The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.
<h3>What is mechanical energy?</h3>
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
A boy is trying to roll a bowling ball up a hill. The friction is ignored. The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
M.E bottom of hill = M.E on top of hill
Kinetic energy + Potential energy = Kinetic energy + Potential energy
1/2 mu² + 0 = 0 + mgh
At the top of hill, the velocity will become zero. So, final kinetic energy is zero.
Substituting the values, we have
1/2 x u² = 9.8 x 22.5
u = sqrt [2 x9.8 x 22.5 ]
u= 21 m/s
Thus, the minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s.
Learn more about mechanical energy.
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