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3 years ago

Help Please

2 answers:

5 0

Since the baseball is half the weight of the softball, the baseball has to go twice as fast as the softball.

So the best answer would be D

inessss [21]3 years ago

5 0

Answer:

D.) The baseball is thrown at 50 m/s and the softball is thrown at 25 m/s.

Explanation:

mass of ball 1

$m_1 = 140 grams$

mass of ball 2

$m_2 = 280 grams$

now we know that if the momentum of two balls are same then we will have

$P_1 = P_2$

$m_1v_1 = m_2 v_2$

so we have

$140 v_1 = 280 v_2$

$v_1 = 2 v_2$

so velocity of light ball must be twice the velocity of heavy ball

so correct answer will be

D.) The baseball is thrown at 50 m/s and the softball is thrown at 25 m/s.

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A small toy car travels 2.0 meters in 120 seconds. what is the speed of the car?

mamaluj [8]

Answer: $\dfrac{1}{60} ms^{-1}$

Explanation:

Speed of an object is defined as the ratio of the distance covered by the object to the time taken to cover that distance.

Let $s$ be the speed of the object.

Let $D$ be the distance travelled by the object.

Let $t$ be the time taken by the object.

So, $s=\frac{D}{t}$

s= $\frac{2}{120}=\frac{1}{60}ms^{-1}$

So,the speed of the car is $\frac{1}{60}ms^{-1}$

4 0

3 years ago

Which of the following is responsible for keeping objects on the ground?

antoniya [11.8K]

Answer:

Gravity. It is the pull we feel. Neither motion could happen nor mass could keep us on the ground without the existence of gravity.

3 0

3 years ago

Read 2 more answers

A 50 kg child runs off a dock at 2.0 ms (horizontally) and lands in a waiting rowboat of mass 150 kg. At what speed does the row

Alex73 [517]

Answer:

The boat moves away from the dock at 0.5 m/s.

Explanation:

Hi there!

Since no external forces are acting on the system boy-boat at the moment at which the boy lands on the boat, the momentum of the system is conserved (i.e. it remains constant).

The momentum of the system is calculated as the sum of the momentum of the boy plus the momentum of the boat. Before the boy lands on the boat, the momentum of the system is given by the momentum of the boy.

momentum of the system before the boy lands on the boat:

momentum of the boy + momentum of the boat

m1 · v1 + m2 · v2 = momentum of the system

Where:

m1 and v1: mass and velocity of the boy.

m2 and v2: mass and velocity of the boat.

Then:

50 kg · 2.0 m/s + 150 kg · 0 m/s = momentum of the system

momentum of the system = 100 kg m/s

After the boy lands on the boat, the momentum of the system will be equal to the momentum of the boat moving with the boy on it:

momentum of the system = (m1 + m2) · v (where v is the velocity of the boat).

100 kg m/s = (50 kg + 150 kg) · v

100 kg m/s / 200 kg = v

v = 0.5 m/s

The boat moves away from the dock at 0.5 m/s.

5 0

4 years ago

What happens to a circuit's resistance (R), voltage (V), and current (1) when

hammer [34]

Answer:

R increases

V is constant

I decreases

Explanation:

The resistance of a wire is given by the following formula:

$R = \frac{(Resistivity)(L)}{A}$

It is clear from this formula that resistance is directly proportional to the length of wire. So, when length of wire is increased, the resistance of circuit increases.

The voltage in the circuit will be constant as the voltage source remains same and it is not changed.

Now, we can use Ohm Law:

V = IR

at constant V:

I ∝ 1/R

it means that current is inversely proportional to resistance. Hence, the increase of resistance causes the current in circuit to decrease.

Therefore, the correct option will be:

D.

R increases

V is constant

I decreases

6 0

3 years ago

A constant force of 20. newtons applied to a box causes it to move at a constant speed of 4.0 meters per second. How much work i

podryga [215]

The answer is 3) 480 joules

6 0

3 years ago