1. Someone fires a 0.04 kg bullet at a block of wood that has a mass of 0.5 kg. (The block of wood is sitting on a frictionless
surface, so it moves freely when the bullet hits it). The wood block is initially at rest. The bullet is traveling 300 m/s when it hits the wood block and sticks inside it. Now the bullet and the wood block move together as one object. How fast are they traveling?
2. Two kids are roller skating. Amy, with a mass of 55 kg, is traveling forward at 3 m/s. Jenny, who has a mass of 40 kg, is traveling in the opposite direction at 5 m/s. They crash into each other and hold onto each other so that they move as one mass. How fast are they traveling?
3. Jake is bowling with a 8 kg bowling ball. He rolls the ball at 7 m/s, and it hits one stationary pin with a mass of 2 kg. The pin goes flying forward at 12 m/s. How fast is the bowling ball now traveling?
4. John has to hit a bottle with a ball to win a prize. He throws a 0.4 kg ball with a velocity of 18 m/s. It hits a 0.2 kg bottle, and the bottle flies forward at 25 m/s. How fast is the ball traveling after hitting the bottle?
2. Two kids are roller skating. Amy, with a mass of 55 kg, is traveling forward at 3 m/s. Jenny, who has a mass of 40 kg, is traveling in the opposite direction at 5 m/s. They crash into each other and hold onto each other so that they move as one mass. How fast are they traveling?
3. Jake is bowling with a 8 kg bowling ball. He rolls the ball at 7 m/s, and it hits one stationary pin with a mass of 2 kg. The pin goes flying forward at 12 m/s. How fast is the bowling ball now traveling?
4. John has to hit a bottle with a ball to win a prize. He throws a 0.4 kg ball with a velocity of 18 m/s. It hits a 0.2 kg bottle, and the bottle flies forward at 25 m/s. How fast is the ball traveling after hitting the bottle?
2 answers:
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initially, the car is traveling at 5.0 m/s.
so, we know acceleration for changing velocity is :
a = (v-v)/t ..........(i)
where v is the final velocity
v is the initial velocity
t is the time taken to change velocity
Now, as per the question :
initial velocity, v=5.0 m/s
final velocity, v =11 m/s
time taken, t = 3 s
putting the values in equation (i),
a = ( 11-5 )/3
a = 2 m/s²
Therefore, a, after 3 s, is <em>2 m/s².</em>
Answer:
The energy that the truck lose to air resistance per hour is 87.47MJ
Explanation:
To solve this exercise it is necessary to compile the concepts of kinetic energy because of the drag force given in aerodynamic bodies. According to the theory we know that the drag force is defined by
Our values are:
Replacing,
We need calculate now the energy lost through a time T, then,
But we know that d is equal to
Where
v is the velocity and t the time. However the time is given in seconds but for this problem we need the time in hours, so,
(per hour)
Therefore the energy that the truck lose to air resistance per hour is 87.47MJ