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2 years ago

7

You push your friend, whose mass is 54kg, down a hill so she can go sledding. Her acceleration is 3m/s2. Calculate the amount of

force you applied to your friend.

1 answer:

Alecsey [184]2 years ago

3 0

Answer:

18 newtons

Explanation:

Divide weight by speed

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P and s waves from an earthquake travel at different speeds, and this difference helps in locating the earthquake âepicenterâ (w

mamaluj [8]

Although the speeds are different, but the two waves will reach the same station so the same distance.

dp = ds

The formula for distance given velocity and time is:

d = v t

Substituting this to the 1st equation:

vp tp = vs ts

Since p wave arrived 2 min (120 s) earlier than s wave, therefore

tp = ts - 120

Then,

vp (ts – 120) = vs ts

8.5 (ts – 120) = 5.5 ts

8.5 ts - 1020 = 5.5 ts

3 ts = 1020

ts = 340 s

tp = ts – 120 = 340 – 120 = 220 s

Then using either dp or ds, we can calculate how far away the earthquake is:

dp = vp tp

dp = 8.5 * 220

dp = 1870 km = 1.9 * 10^3 km

8 0

3 years ago

A moving curling stone, A, collides head on with stationary stone, B. Stone B has a larger mass than stone A. If friction is neg

Kitty [74]

Answer:

The correct answer is option 'c': Smaller stone rebounds while as larger stone remains stationary.

Explanation:

Let the velocity and the mass of the smaller stone be 'm' and 'v' respectively

and the mass of big rock be 'M'

Initial momentum of the system equals

$p_i=mv+0=mv$

Now let after the collision the small stone move with a velocity v' and the big roch move with a velocity V'

Thus the final momentum of the system is

$p_f=mv'+MV'$

Equating initial and the final momenta we get

$mv=mv'+MV'\\\\m(v-v')=MV'.....i$

Now since the surface is frictionless thus the energy is also conserved thus

$E_i=\frac{1}{2}mv^2$

Similarly the final energy becomes

$E_f=\frac{1}{2}mv'^2+\frac{1}{2}MV'^2$ \

Equating initial and final energies we get

$\frac{1}{2}mv^2=\frac{1}{2}mv'^2+\frac{1}{2}MV'^2\\\\mv^2=mv'^2+MV'^2\\\\m(v^2-v'^2)=MV'^2\\\\m(v-v')(v+v')=MV'^2......(ii)$

Solving i and ii we get

$v+v'=V'$

Using this in equation i we get

$v'=\frac{v(m-M)}{(M-m)}=-v$

Thus putting v = -v' in equation i we get V' = 0

This implies Smaller stone rebounds while as larger stone remains stationary.

4 0

2 years ago

How to play track and field

Ahat [919]

Explanation:

Track and Field is a sport, which is includes disciplines of running, jumping, and throwing events. The sport traces back to Ancient Greece. The first recorded examples of this sport were at the Ancient Greek Olympics. In Ancient Greece, only one event was contested, the stadion footrace. Later on, the game expanded to more events.Events of track and field are divided into three: track events, field events, and combined events. Track events consist of Sprints, middle-distance, long distance, hurdles and relays; Field events consist of jumps and throws; while combined events consist of pentathlon, heptathlon, and decathlon. Track and field is usually played outdoors in stadiums. The usual features of a track and field stadium are the outer running track, and the field within the track

3 0

3 years ago

Read 2 more answers

A 60 kg skier starts from rest at the top of a frictionless slope of height of 35 meters. The velocity at the bottom is v. If a

Solnce55 [7]

Answer:

Explanation:

Speed of skier without parachute

= √ 2gh

= √ 2 x 9.8 x 35

= 26.2 m / s

Speed of skier with parachute

net force downwards

mg - 200

= 60 x 9.8 -200

= 388 N

acceleration = 388 / 60

a = 6.47 m / s

v = √ 2ah

= √ 2 x 6.47 x 35

= 21.28 m / s

8 0

2 years ago

Read 2 more answers

Both physical and chemical changes are accompanied by a change in the total energy of the system, which is divided into two broa

olga2289 [7]

Answer:

I believe <u>kinetic / potential</u>

Explanation:

8 0

1 year ago