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3 years ago

An object accelerates at 10 m/s2. If its starting velocity is 20 m/s and it travels for 30 seconds, what is its final velocity?

Physics

1 answer:

polet [3.4K]3 years ago

8 0

Answer:

320m/s

Explanation:

Step 1: State your values

s= NOT NEEDED

u=20m/s

v=?

a=10m/s²

t=30 seconds

Step 2: Find a suitable suvat equation:

v=u+at

Step 3:

subsitute values into equation:

?=20+(10x30)

20+300

320m/s

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A 7382 N piano is to be pushed up a(n) 2.16 m frictionless plank that makes an angle of 22.7 ◦ with the horizontal. Calculate th

lubasha [3.4K]

Answer:

Work done, W = 6153.31 Joules

Explanation:

It is given that,

Weight of piano, W = F = 7382 N

It is pushed 2.16 meters friction less plank

The angle with horizontal, $\theta=22.7^{\circ}$

When the piano slide up plank at a slow constant rate. The y component of force is taken into consideration. The net force acting on it is given by :

$F_y=F\ sin\theta$

Work done is given by :

$W=F_y\times d$

$W=F\ sin\theta \times d$

$W=7382 sin(22.7) \times 2.16$

W = 6153.31 Joules

So, the work done in sliding the piano up the plank is 6153.31 Joules. Hence, this is the required solution.

7 0

2 years ago

Train cars are coupled together by being bumped into one another. Suppose two loaded cars are moving toward one another, the fir

tia_tia [17]

Answer:

7560 Joules

Explanation:

$m_1$ = Mass of first car = $1.5\times 10^5\ kg$

$m_2$ = Mass of second car = $2\times 10^5\ kg$

$u_1$ = Initial Velocity of first car = 0.3 m/s

$u_2$ = Initial Velocity of second car = -0.12 m/s

v = Velocity of combined mass

As linear momentum of the system is conserved

$m_1u_1 + m_2u_2 =(m_1 + m_2)v\\\Rightarrow v=\frac{m_1u_1 + m_2u_2}{m_1 + m_2}\\\Rightarrow v=\frac{1.5\times 10^5\times 0.3 + 2\times 10^5\times -0.12}{1.5\times 10^5 + 2\times 10^5}\\\Rightarrow v=0.06\ m/s$

Energy lost is

$\Delta E=\Delta E_i-\Delta E_f\\\Rightarrow \Delta=\frac{1}{2}(m_1u_1^2 + m_2u_2^2-(m_1+m_2)v^2)\\\Rightarrow \Delta=\frac{1}{2}(1.5\times 10^5\times 0.3^2 + 2\times 10^5\times (-0.12)^2-(1.5\times 10^5 + 2\times 10^5)\times 0.06^2)\\\Rightarrow \Delta=7560\ J$