All categories

4 years ago

John pushes his brother Danny on a skateboard. John applies a force of 29 N and Danny's acceleration is 0.4 m/s

Physics

2 answers:

belka [17]4 years ago

4 0

Answer:

Explanation:

Mumz [18]4 years ago

4 0

Answer:

The combined mass of Danny and his skateboard = m = 72.5 kg

Explanation:

Force applied by john = F = 29N

Danny’s Acceleration = a = 0.4 m/s

Combined mass of Danny and his skateboard = m = ?

According to Newton’s second law of motion:

F = ma

m = F/a

m = 29/0.4

m = 72.5 kg

Hence, the combined mass of Danny and his skateboard will be 72.5 Kg.

You might be interested in

A 70.0-kg skier is sliding at 4 m/s when they slide down a 2m high hill. At the bottom of the hill they run into a large 2800 N/

Katarina [22]

Answer:

$\Delta x=245\ mm$

Explanation:

Given:

mass of skier, $m=70\ kg$

initial velocity of skier, $u=4\ m.s^{-1}$

height of the hill, $h=2\ m$

spring constant, $k=2800\ N.m^{-1}$

final velocity of skier before coming in contact of spring:

Using eq. of motion:

$v^2=u^2+gh$

$v^2=4^2+9.8\times 2$

$v=5.9666\ m.s^{-1}$

Now the time taken by the skier to reach down:

$v=u+gt$

$5.9666=4+9.8\ t$

$t=0.2007\ s$

Now we calculate force using Newton's second law:

$F=\frac{dp}{dt}$

$F=\frac{m(v-u)}{t}$

$F=\frac{70\times(5.9666-4)}{0.2007}$

$F\approx686\ N$

∴Compression in spring before the skier momentarily comes to rest:

$\Delta x=\frac{F}{k}$

$\Delta x=\frac{686}{2800}$

$\Delta x=0.245\ m$

$\Delta x=245\ mm$

4 0

3 years ago

Rex makes himself a bowl of cereal. He puts 28 g of cereal in a bowl and then adds 245 g of milk. Before eating the cereal, he r

Galina-37 [17]

Answer:

A.)

Explanation:

Because you didn't add anything or take anything away.

5 0

3 years ago

g A raindrop charged to 10 mC experiences electric field of 10,000 V/m from a tip of a tree branch. What is the electric force a

Andrews [41]

Answer:

The electric force acting on the raindrop is 100 N.

Explanation:

Given;

charge of the raindrop, Q = 10 mC = 0.01 C

electric field strength, E = 10,000 V/m = 10,000 N/C

The force acting on the raindrop is given as;

Electric Force = electric field strength x charge of the raindrop

F = EQ

F = (10,000 N/C) (0.01 C)

F = 100 N

Therefore, the electric force acting on the raindrop is 100 N.

4 0

3 years ago

Calculate the charge of a copper particle of mass 300 mg, if 0.01% of the electron are removed from it

Alex73 [517]

Answer:

the charge will be neutral.

Explanation:According a book, metals want to "lose" electrons to achieve noble gas configuration. But at the same time, copper ions in a galvanic element are going to gain electrons from a zinc electrode. Why is it so? Is it because one of them HAS to gain/lose electrons, and zinc wins out in terms of achieving noble gas configuration?

6 0

3 years ago

Two light bulbs, A and B, are connected to a 120-V outlet (a constant voltage source). Light bulb A is rated at 60 W and light b

d1i1m1o1n [39]

Answer:

Bulb A has a greater resistance.

Explanation:

Electric power (P) = V²/R

P = V²/R................ Equation 1

Where P = power, V = Voltage, R = Resistance.

Make R the subject of the equation

R = V²/P ................ Equation 2

For Bulb A,

Given: V = 120 V, P = 60 W.

Substitute into equation 2

R = 120²/60

R = 240 Ω

For bulb B

Given: V =120 V, P = 100 W.

Substitute into equation 2

R = 120²/100

R = 14400/100

R = 144 Ω

Hence Bulb A has a greater resistance.

5 0

3 years ago