A solid ball with a mass of 4.25 kg and a

A 2kg bowling ball rolls at a speed of 5 m/s on a roof of the building that is 40 meters tall. What is the kinetic energy

MrRa [10]

The kinetic energy is $\frac 1 2 m v^2$ and the height of the building doesn't matter at all.

$E = \frac 1 2 m v^2 = \frac 1 2 (2)(5)^2 = 25$ joules

8 0

2 years ago

If the bonds in the reactants of Figure 7-3 contained 432 kJ of chemical energy and the bonds in the

Yuri [45]

Answer:

The energy change would be 46kJ

The energy would be absorbed

Explanation:

The energy change during a chemical reation, i.e. the reaction energy, is equal to the chemical energy stored in the bonds of the products less the chemical energy stored in the bonds of the reactants.

Hence:

Energy change = 478 kJ - 432kJ = 46kJ

The change is positive, this is, the chemical energy of the products is greater than the chemical energy of the reactants.

That corresponds to the second graph, where the level of the energy of the products in the graph is higher than the level of the energy of the reactants. Therefore, the conclusion is that the reaction absorbed energy and it is endothermic.

4 0

3 years ago

A ball is thrown vertically upwards from the edge of the cliff and hits the ground at the base of the cliff with a speed of 30 m

olya-2409 [2.1K]

To solve this problem we will apply the linear motion kinematic equations. From the definition of the final velocity, as the sum between the initial velocity and the product between the acceleration (gravity) by time, we will find the final velocity. From the second law of kinematics, we will find the vertical position traveled.

$v = v_0 -gt$

Here,

v = Final velocity

$v_0$ = Initial velocity

g = Acceleration due to gravity

t = Time

At t = 4s, v = -30m/s (Downward)

Therefore the initial velocity will be

$-30 = v_0 -9.8(4)$

$v_0 = 9.2m/s$

Now the position can be calculated as,

$y = h +v_0t -\frac{1}{2}gt^2$

When it has the ground, y=0 and the time is t=4s,

$0 = h+(9.2)(4)-\frac{1}{2} (9.8)(4)^2$

$h = 41.6m$

Therefore the cliff was initially to 41.6m from the ground

7 0

2 years ago

A karate master wants to break a board by hitting the board swiftly with his hand. The master's hand has a mass of 0.30 kg, and

slava [35]

Answer:

f=-1380N

Explanation:

A karate master wants to break a board by hitting the board swiftly with his hand. The master's hand has a mass of 0.30 kg, and as it strikes the board, his hand has a velocity of 23.3 m/s. The master contacts the board for 0.0050 seconds

.the concluding part to the question should be

What is the impact force (impulse) on the board?

solution

from the Newton's second law of motion which states that

the rate of change in momentum is directly proportional to the force applied

f=m(v-u)/t

f=0.3(0-23.3)/0.005

f=-1380N

f=force impact

m=mass of the karates master's hand

t=time for the impact

v=0m/s final velocity

u=initial velocity

6 0

3 years ago

A combined circuit has two resistors in series (27.5 ohms and 33.0 ohms) and another in parallel (22.0 ohms). If the power sourc

Dafna1 [17]

R 1,2 = 27.5 + 33.0 = 60.5 Ohms
1/ R 1,2,3 = 1/ 60.5 + 1 / 22 = 82.5 / 1331
R 1, 2, 3 = 1331 / 82.5 = 16.13 Ohms
I = U / R
I = 9 V / 16.13 Ohms = 0.557 A ≈ 0.56 A
Answer: C ) 0.56 Amps

4 0

3 years ago