What is phylenogeny?
2 answers:
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7) 2,197 kg
The weight of an object on Earth is given by:
where m is the mass of the object and is the acceleration due to gravity. Since we know the weight of the object, W=21,532 N, we can re-arrange the equation to calculate the object's mass:
8) 2,197 kg
Mass is an intrinsec property of an object: it says "how much matter" is contained within an object. Therefore, the mass of an object does not depend on its location: so, the object has the same mass on Earth and on the moon, and so its mass is still the same as the previous exercise, 2,197 kg.
9) 187,500 N
The force exerted on an object is given by Newton's second law:
where m is the mass of the object and a its acceleration. In this problem, and
, so the force exerted on the object is
10) 2nd Law
Newton's second law states that an object which is acted upon a force experiences an acceleration given by:
where F is the force and m the mass of the object. As a result, the object accelerates, so if it was at rest, it starts moving.
This is exactly what happens in this example: the ball is initially at rest, but then a force is applied on it (by the kick), so the ball is accelerated and it starts moving.
<h2><u>Full Question:</u></h2>
The table shows the changes in velocity for several different cars. Each change takes place over a 10-second interval. Which cars are either
speeding up or slowing down?
Starting Velocity
Ending Velocity
Car A
30 km/h
30 km/h
Car B
O km/h
20 km/h
Car C
30 km/h
O km/h
Car D
O km/h
O km/h
Car E
20 km/h
30 km/h.
<h2><u>Answer:</u></h2>Acceleration is present in car B and E.
Deceleration is present in car C.
No change in velocity is seen in car A and D.
<h3><u>Explanation:</u></h3>Acceleration is defined as the rate of change of velocity with time and is having a dimensional formula of
When a body is having acceleration, the body has more final velocity than initial velocity. Deceleration is the opposite of acceleration which is seen when the body has less final velocity than initial velocity.
In A:
Initial velocity= 30 km/hr.
Final velocity= 30 km/hr.
So change in velocity = 30-30 km/hr = 0 km/hr.
So no acceleration is present.
In B:
Initial velocity= 0 km/hr.
Final velocity= 20 km/hr.
So change in velocity = 20-0 km/hr = 20 km/hr.
So acceleration is present.
In C:
Initial velocity= 20 km/hr.
Final velocity= 0 km/hr.
So change in velocity = 0-20 km/hr = -20 km/hr.
So deceleration is present.
In D:
Initial velocity= 0 km/hr.
Final velocity= 0 km/hr.
So change in velocity = 0-0 km/hr = 0 km/hr.
So no acceleration is present.
In E:
Initial velocity= 20 km/hr.
Final velocity= 30 km/hr.
So change in velocity = 30-20 km/hr = 10 km/hr.
So acceleration is present.