Answer:
B. A car of mass 2000 kg with speed 7 m/s
Explanation:
The kinetic energy of an object is given by:
where m is the mass of the object and v is its speed.
From the formula, we see that the larger the mass and the speed of the object, the larger its kinetic energy. Among the choices given, we see that the car with largest mass and largest speed is car B, which has a mass of 2000 kg and speed of 7 m/s. Its kinetic energy is:
We can verify that the other cars have smaller kinetic energy. In fact:
- Car A: 
- Car C: 
- Car D: 
So, car B is the one which has most kinetic energy.
10 seconds 25m*10s= 250m
60 seconds 25m*60s=1500m
Answer:
Explanation:
It is given that,
Mass of the baseball, m = 0.14 kg
It is dropped form a height of 1.8 m above the ground. Let u is the velocity when it hits the ground. Using the conservation of energy as :
h = 1.8 m
u = 5.93 m/s
Let v is the speed of the ball when it rebounds. Again using the conservation of energy to find it :
h' = 1.4 m
v = -5.23 m/s
The change in the momentum of the ball is given by :
So, the change in the ball's momentum occurs when the ball hits the ground is 1.56 kg-m/s. Hence, this is the required solution.
-- She went up for 0.4 sec and down for 0.4 sec.
-- The vertical distance traveled in gravity during ' t ' seconds is
D = (1/2) x (g) x (t)²
= (1/2) (9.8 m/s²) (0.4 sec)²
= (4.9 m/s²) x (0.16 s²)
= 0.784 meter ( B )
Answer:
D. It is relatively inert.
Explanation:
