Question

A truck starts from rest and rolls down a hill with constant acceleration. it travel a distance of 800m in 40 s. find the force and acceleration. if its mass is 7tonnes (hint :1 tonnes =1000kg.)​

Answer 1

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The truck starts from rest, so initial velocity = 0

$⇝$Distance travelled = 800 m

$⇝$Time taken = 40 s

$⇝$According to the 2nd equation of motion

$⇝$s = ut + ½ at²

$⇝$ 800 = 0*40 + ½ × a × (40)²

$⇝$ 800 = 0 + ½ × a × 1600

$⇝$ 800 = 800a

$⇝$ a = 800/800 = 1m/s²

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acceleration of truck is 1m/s²

as we know :-

$⇝$Force = mass × acceleration

$⇝$ F = m × a

$⇝$ F = 7000 × 1

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$⇝$F = 7000 N

Answer 2

Gɪᴠᴇɴ :-

• Initial velocity (u) = 0
• Distance travelled (s) = 800m
• Time taken (t) = 40s
• Mass (m) = 7 tonnes = 7*1000 = 7000kg

ᴛᴏ ғɪɴᴅ :-

• Force and acceleration of truck

sᴏʟᴜᴛɪᴏɴ :-

According to the 2nd equation of motion

→ s = ut + ½ at²

→ 800 = 0*40 + ½ × a × (40)²

→ 800 = 0 + ½ × a × 1600

→ 800 = 800a

→ a = 800/800 = 1m/s²

Hence,

• Acceleration of truck is 1m/s²

As we know that

→ Force = mass × acceleration

→ F = m × a

→ F = 7000 × 1

→ F = 7000 N

Hence,

• Force = 7000 Newton